Check the middle of the bump first
A pimple starts when a hair follicle under the skin clogs, which is why you'll often see a white plug at the center (MedlinePlus). A tick is a separate animal that has attached to feed, so you're looking for legs, a small oval body, or a mouth end sitting at the skin. Use bright light, and if the bump is on your back or scalp, ask someone to look for you.
Don't rule out a tick because the bump is tiny. Before it feeds, a tick can be as small as a poppy seed (NIH News in Health), some are too small to notice at all, and you often won't feel the bite (MedlinePlus). A small red spot where a tick bit you is normal. It doesn't mean you have Lyme disease, and it usually fades in a day or two (American Academy of Family Physicians).
A tick that's feeding changes size, which is why a speck this morning can look like a pimple tonight. It can stay attached for several days and swell to ten times its size or more (NIH News in Health). If a bump is new after a walk through brush, compare it with how it looked earlier in the day, in the same light.
Where on your body it is
Pimples gather on the face, neck, back, chest, and shoulders, and they're most common in teenagers and young adults (MedlinePlus). A cluster of similar bumps along your chin that has been there for weeks is almost certainly acne. Ticks don't produce a crop like that.
Ticks go where it's warm and hard to see. People most often find them in the groin, armpits, and scalp (FDA), and the ears, waist, backs of the knees, and ankles are worth checking too (Nemours KidsHealth). One new bump in one of those places after a hike deserves a close look before you call it a zit.
Who else has it can help. If three people in the house have matching bumps and nobody has been near the woods, think acne or folliculitis. If one person has one new bump after a walk in tall grass, think tick first.
Ingrown hairs, razor bumps, and sock rub
Folliculitis is inflammation of the hair follicles. It starts when a follicle is damaged or blocked, often by shaving or by clothing rubbing the skin, and it looks like pimples near a hair that may crust over (MedlinePlus). So if the bump is where you shaved, or where a sock cuff or waistband presses, part the hair and look for a tip curling back into the skin.
Curly beard hairs that are cut too short can curve back in and cause inflammation. That has its own name, pseudofolliculitis barbae. Barber's itch is a staph infection of the beard follicles, usually around the upper lip, and shaving makes it worse. Bumps that follow your razor line, with a hair tip in the middle of each, aren't ticks.
The tricky part is that a boot cuff, a waistband, and a shaved groin are also places where ticks attach. If you can't tell a buried hair from a small tick, don't dig at it. Get better light, or have someone else look. If the bumps keep coming back, get worse, or last longer than two or three days, contact a clinician.
Why you shouldn't squeeze it
Squeezing is the wrong move for both, for different reasons. Never crush a tick with your fingers, because not every tick carries the same germs and you don't want its fluids pushed into your skin (FDA). Don't twist it, smother it in oil or petroleum jelly, or burn it either (MedlinePlus).
If you can see a tick, grip it with tweezers as close to the skin as you can and pull straight out. Wash the skin and your hands with soap and water afterward, and write down the date. Taking a tick off before it has filled with blood makes infection less likely (MedlinePlus), so don't wait until morning if you can see one tonight. If a mouthpart stays in the skin, it usually grows out on its own, though a local infection is possible (MedlinePlus).
For a follicle that's inflamed, the usual advice is warm, moist compresses rather than picking at it. If a bump becomes more painful, warm, and full of pus, or a red streak starts to spread away from it, contact a clinician instead of treating it yourself.
When it's neither one
A bump that spreads is a different question. An early Lyme rash is a reddish, round patch that slowly gets bigger over several days. It usually doesn't itch or hurt, it may feel warm, and it can turn into a bull's-eye later, though not always (MedlinePlus). A whitehead doesn't do that. If a spot is growing and flattening into a patch, stop treating it as acne and call a clinician. The bullseye rash page shows what a ring can look like.
Get care now if you have trouble breathing, swelling of your face or mouth, or a red area that's spreading fast over hours. And if you're not even sure the mark is a bite, the bite or something else quiz can help you sort that out first.
What to do tonight
Here's the short version, depending on what you find at the center.
- Legs or a small body: take it off with tweezers at the skin, wash up, and keep the date in case you need to tell a clinician later.
- A white plug or a hair tip: leave it alone, use a warm compress, and get it looked at if it keeps returning, worsens, or hangs on past two or three days.
- A patch that keeps growing, or trouble breathing: get medical care instead of waiting to see.
Still not sure?
If you can't settle it by looking, photograph the bite, or the tick if you still have it, in the BiteSight iPhone app. If you don't have an iPhone, the same photo tool works on the web. There's no Android app yet.
