A rash appeared on my butt a couple weeks ago. the rash was very red but not painful and not that itchy. there were bright red blotches. the rash was confined to the center of my butt cheeks where my anus is but did not go inside my crack or elsewhere. it appeared after a night of heavy drinking (beer). A few days earlier I had unprotected vaginal sex. i went to my doctor who was unsure of what it was but said it was most likely contact dermatitis and prescribes a steroid cream and said to come back if it spread. 2 weeks later the rash had basically healed and i woke up with what looks like a cluster of mosquitoe bites in the same area. 2 days after another night of drinking beer. this rash is not the same as before as it resembles mosquito bites insteas of the bright red rash i had before but it seems as though it is spreading when i scratch it. it is far itchier this time as well. any ideas as to what this may be?