tiny blisters on my big toe

I have been getting several tiny little blisters all over my big toe, they go away then they come back like it is cyclic. The blisters pop and dry out causing my toe to crack in several different places. This condition has not spread to any other toes so i don't believe it is contagious. This all started a few years ago when i was at a public pool and cut my toe while in the pool. Prior to that i had never had this problem. My doctor insists that it is just athlete's foot, however having been prescribed the medicated creams, it still does not go away. I have also been told that it may be plantar warts but i have read that plantar warts is contagious. Any ideas?