Seems that it’s quite usual for bites to continue to develop for a week or so after returning from holiday.
It’s probably really obvious, but if your bites persist for a long time, or if they are “oozy” and don’t get better right away with antibiotic cream, go to a doctor. You might have an infection there.
There’s a tropical disease called Leishmaniasis which is carried in the bite of sand fleas (or no see-ums). THIS DISEASE IS NOT ENDEMIC IN CUBA. That doesn’t mean it’s 100% impossible to get it there, but it’s super-unlikely.
The literature says that a DEET based repellant is effective against sand fleas/no see-ums. However, from people’s accounts, this doesn’t sound like it’s worked very well. Any opinions?