What happens when a sebaceous cyst ruptures?

It heals.: Contents spill out. Inflammation subsides. Cyst heals. Sometimes recurs.

It starts to heal: Most sebaceous cysts do not rupture on their own without some "help" in the form of picking, squeezing, or popping with a needle. If they become infected, they can indeed rupture, and then they begin to heal. If the sac that forms the sebaceous material remains, the cyst can recur. Surgical excision or drainage (with sac removal) gives the best chance of non-recurrence and least scarring.

Depends: If it ruptures internally, it causes an inflammatory reaction. If it ruptures to the outside through a small opening the contents may dry up and grow like a horn, albeit very slowly, The rupture may allow the lesion to heal also. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.