How long can i wait with skin ulcers to see if it goes away without seeing a doctor?

Never hurts to check: Most simple skin ulcerations can be treated initially with simple first aid such as cleaning and triple antibiotic ointment, usually applied once or twice a day. Persistent bleeding, increasing redness around the ulcer, increasing pain and simply non-healing after let's say 3 days of the above treatment are excellent reasons to have your pcp check it out.