I have a ulcer on my toe what should i do?

Don't self treat: An ulcer can get worse very fast, you need to see a podiatrist asap.

Get treated: Ulcers on the feet are hard to treat because there is constant pressure on the area, making it hard to heal. If infected, you will need antibiotics possibly, etc. Best to get evaluated and told how long to stay off the area, get meds, possible debridement if needed, etc. Best wishes.