Been having these bites for a month

I really don't know what these are, we've been looking for bugs in our room the whole time and can't find anything, my mother-in-law, who lives in the same house, doesn't have them :( The bites itch, are red and are all over my hands and forearms. They're also very close together in groups. Not sure if you can see the ones on my arm well, the blood is from scratching.