I think i have a blister on the ball of my foot below my big toe. it hurts when i walk on it. what should i do? how to avoid in the future?

Blister: These are caused by friction. Either from an ill fitting shoe or walking excessively without good foot protection. Make sure when you are walking any distance that you have the proper shoes. No running track in sandals. Do not take the ski off the blister it acts as a sterile covering. A moleskin circle around the blister will take pressure off that area. A podiatrist is helpful.