Hi, I Am An 18 Y/o Girl. I Noticed A

Hi,
I am an 18 y/o girl. I noticed a bump on my butt cheek the other day. It was kind of sore. I felt it under my skin too. It started to itch and I accidently scratched it until it bled. It is flat now but it has a scab. Now there are tons of other bumps surrounding that one. They are barely raised and I cant feel the lump under my skin. They do not hurt but they itch. Im trying not to scratch but it is hard. They are only on my left cheek. I have one or two on my lower back and a few on my upper thigh. It looks like one or two may be appearing on the other cheek but they are too small to tell and don't itch. Should I go to urgent care or the dr? I really don't want these bumps to leave a scar or keep spreading. What could it be? (it is impossible that this is anything sexually transmitted fyi).I also haven't used any new soaps or detergents