I used to get a product in akumal Mexico called bactrim,believe its a antibiotic,one dose usually clears up any symptoms,my guess is you could get that in negril from a pharmacy,go to the right one and it will probably be over the counter,I brought a supply down to cabo for my brothers wedding about 40 people came down,by the 3rd or fourth day I was handing em out like m,n,ms