Fistula, abscese? Would be grateful.

Hi, I had constipation for a couple of days, almost a week ago. And there was blood in my stool. Its topped after two days. But, now ,I have something like a boil developing very close to my anus. And the pain is really bad. I did have fistula ayurvedic treatment almost 10 years ago. But a small part of the anus skin is still coming out. Though the pain is not in this skin part. The pain is in the boil area. Its not a big one as of now, but pains a lot. Also I am not able to shit properly as it pains when I put any pressure. Its been a scary, painful week for me. I kindly request you to suggest me, as to which doctor, speciality Dr. Should I see to get this problem handled :( Any suggestion on clinics in Bangalore would be grateful..