I have a open skin in anus, it burns when wash, its bleeds, how much time does it takes to heal? or what to do to heal , i used to have a rash is gone

See doctor 4 culture: Make sure that a physician sees your open wound on your anus. Also it should probably be cultured to make sure that it's not mrsa, or something else. You want to prevent it from being infected, in this area is close to the rectum were feces comes out. So it's often a difficult area to protect from bacteria.So go to your doctor, and get treated.A site bath twice daily would be good to reduce pain.

Have it checked: Have it checked, it may be a sentinel pile due to fissure and that can cause burning get it checked by your doctor.

See answer: You likely have an anal fissure which is a small split or tear in the thin lining of the anus and usually occur after a large or hard bowel movement. Most fissures heal within 1-2 weeks. Treatments that help healing include: sitz baths, stool softeners, fiber, hydration, and over-the-counter creams/ointments (anusol, anusol-hc, prep h) and pre-medicated pads (tucks) rather than toilet paper.

Proctologist: Do yourself a big favor and consult a proctologist for this problem. I found over the years that the proctologist gives by far the best care and follow up for such problems of anal and rectal disorders like fissures,proctitis, external hemorrhoids,perianal dermatitis,etc.