most likly an allergic reaction. But bed bugs and fleas, spiders are an option. bedbugs can easily be found under the seam of the mattress. Lift it and look. They are big enough to see.

I checked and didn't see any bedbugs. I haven't gotten any bites recently so I'm guessing they're from the t-shirt I bought. I washed it a lot so I can wear it now. Thanks for replying to my topic.

Could be CHIGGERS.
CHIGGERS most commonly bite from the waist down and are found it wooded or grassy areas.
Been out in the woods or any grassy fields lately?

probably is bed bugs. when they bite your face, it usually comes in littel pimle clusters and itch a little but not often. it's not likley that you will see blood spots right a way. people think that bed bugs hide and live in your bed, but in actuality, they live in the wooded areas, base boards in your bed room around your bed. the crawl into your bed, pillow cases at night and bite you when they sense your alseep by the sound of your breathing. you may see black spots in the seems of your bed from feces, but again, bed bood typically dwell in the cracks and crevices of any area. that is why if you ever were to get a bed bug extermination, they would generally treat very tediously, however, all of hte cracks and crevices of you room/home. so don't rule out bed bugs just because you don't see blood spots. it is very common to have bed bugs with not many traces at all aside from the bites for a significant period of time unless you home is really infested.