What Causes Burning And Itching Sensation In Between Buttocks?

Hi I have had a problem before with the top of tge butt Crack itching then the burn after I itch it usually goes away after I put lotion in it for a few days. (I think that is only dry stretched skin) but I m having a different kind of problem in the same area it itches but no burn yet I looked at it and it looks like it a patch of infused blisters can it be a std or a infection?