Hi Seeing a blister filled with blood is nothing to panic about. Blood blisters are fairly common and are generally caused by injury without the skin breaking or by friction. The best treatment for a blood blister is to let it heal on its own over a few weeks. There are cases, however, when you should see your doctor: You notice symptoms of infection such as warmth, or red lines leading away from the blister. The blister is making it difficult for you to use your hands. The blister seemed to appear for no reason. There are multiple blisters on your skin and you don’t know why. The blister keeps coming back. Keep the blood blister protected as it heals. You may want to wrap it in a protective layer, such as a bandage. If the blister hurts, you can apply ice wrapped in a towel to it. Hope I have answered your query. Let me know if I can assist you further. Regards Dr.Saranya Ramadoss, General and Family Physician