Insect bites on my legs, they swell up to the size of a pint glass making it painful to walk. am i allergic to them? not had this reaction before?

Insect bites: It would appear you are quite allergic to insect bites. See an allergist to be tested and treated for insects

See a dermatologist: Not an allergist. You assume these to be insect bites, and some people have exaggerated reactions to mosquitoes, but this is suspicious for something else. You need to begin with a precise definition of the problem so you will be able to get help.