Hi, it may be herpes, and if you go to your doc they can take a simple swab of it and have it tested, If it is there are anti virals that can help you. If you are in an outbreak do not have sex with anyone until it has cleared up. Dont touch your eyes, as it can get into your eyes, not as easy but it happens. It is easy to test for, and easy to treat, but no cure. There may be other symptoms with an outbreak as well, it can cause you to not feel well, and some other things. If it is genital herpes there are message boards out there if you need support. :)…If this is herpes, it looks like the blisters are almost healed, herpes blisters will be painful, filled with clear fluid and can be on the front, or back, and in the butt crack as well. Almost anywhere below the belly button. But usually around the genitals. They will usually come in a cluster, but not always, can be just one or 2. People have outbreaks if they are under stress, during their period, or the change of the seasons. 
It is hard to tell on the pic, but are these perfectly round?..it may be ringworm , but just cant tell, if it is it us also easily curable too.
Ringworm: More commonly known as jock itch, ringworm is a fungal infection that causes a red, ring-shaped rash in the groin and butt area. The rash is often very itchy. … An infection in the hair follicles from shaving or general friction (folliculitis) causes acne on the butt.
What causes ringworm on the buttocks?
Jock itch, also called tinea cruris, is a common skin infection that is caused by a type of fungus called tinea. The fungus thrives in warm, moist areas of the body and as a result, infection can affect the genitals, inner thighs and buttocks.
Ringworm typically starts out as red or pink skin patches (or spots) that may be either flat or slightly raised. In this initial stage, the sores may be moist, but more often they’re dry, scaly, and itchy. … If you scratch the rash you may break the skin, which could lead to a bacterial infection…
good luck…