Hello, You are advised to take care of your hygiene. Keep the area affected clean. Take antihistamine at bedtime. It will reduce in size if it is an insect bite. Apply ointment Soframycin or Hydrocortisone to the area affected. However, if the red bump is fluid filled, applying topical Hydrocortisone ointment / cream will help to get rid of it. If it is a cold sore, it is caused by herpes. Antivirals and ointment Acyclovir are needed. Blood blisters don’t require treatment and heal by themselves. Apply antibacterial cream after cleaning. Protect the site by bandaging to heal. Do not let it get infected. You can get a biopsy done, to be on the safer side. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K, General & Family Physician