I have a large swollen painful bump in the crease of the bottom of my rear and leg- i see here it may be an abscess. what doctor should i see for this? an obgyn? a physician? i've tried to drain it myself (cleaned it after) and had no success?

I would recommend that you start with your primary care physician (internist, pediatrician, family practitioner). If you don't have a regular doctor, go to an urgent care or the ER. Either place will also be able to examine you and advise as to treatment. If the abscess needs to be drained, they may refer you to a surgeon. Meanwhile, don't try to drain it yourself, but do apply warm compresses.