How to prevent oral cyst from forming after accidentally biting my lip? It has happened twice before, it is now just a small white patch that hurts

Keep the area clean. Keep the area clean with swapping the area with salt water by using q-tip. The small white patch will heal. If there is a colorless or bluish bump develop called mucocele, which is a salivary deposit in the soft tissue due to rupture minor salivary gland and/or duct. Mucocele can be removed by your dentist/surgeon. See your dentist to check your occlusion to eliminate the cause of lip biting.
Biting your lip. Sorry, it's a silly obvious answer, but it is true. Irritation will eventually provoke your body into "defending itself" often by forming cysts. Biting your lip is probably a nervous habit.See your dr. Have the lesion removed and learn of other ways to cope with your tension and nervousness besides biting your lip. Meditation, deep breathing, yoga, tai chi... There are many ways to cope w/stess.