This varies a lot from person to person. My mom doesn’t have any kind of reaction to mosquito bites. My dad gets angry red welts. They grew up in the same town and have been living together for 50 years. Spending more time in a place with mosquitoes is not going to help him.
After a couple of weeks of this, I redeveloped my resistance to them and no longer even notice them anymore.
Of course this doesn't apply if there's an ongoing mosquito-borne epidemic in your area, but that doesn't happen often. When they're not carrying a disease (which is most of the time), they're pretty harmless.