What Causes Pain And Skin Tear In Between Buttocks?

So before coming online i was sure i was the only person with this problem, much to my surprise there are tons of ppl out there with the same issue. It s a reoccurring problem i have been experiencing. Between my butt cheeks the skin seems to getting torn/split. It s quite painful, very uncomfortable, lots of itching, and sometimes when it itches little bumps come up on the skin just above the butt crack. In the mean time i don t know what to do, it s been about a week already, seems to be getting worse rather than better. If I bend it feels like it is splitting even more. Sitting for long periods has become quite uncomfortable. The itching won t stop. I have been using vaseline on it with hopes it would help. It does soothe it, sometimes i use baby oil and the itching subsides for a while then it starts again. So what causes this and what is the most effective treatment.