I have heard bug repelent with deet is hard to find in Mexico and my housekeeper always asks me to bring down multi packs of the CFL light bulbs (4 pack at US home depot about $7USD) that cost abut $8 USD each in Mexico ...
Corbel said, "We've found that deet is not simply a behavior-modifying chemical but also inhibits the activity of a key central nervous system enzyme, acetycholinesterase, in both insects and mammals".
Usually 25% deet is plenty to keep them at bay, if you take a trip back into the lagoons along the coast use the 100%.
So if you actually take deet, which is a chemical which actually ward off mosquitoes, put it all over your body, reapply it only every few hours, if you need to, and don't to use deet with a concentration higher than 35 percent.
The chemical known as deet (for N, N-diethyl-meta-toluamide) is found in nearly every commonly used mosquito repellent in the world, and eight billion doses have been applied since its introduction to the consumer market in 1957.