I have just returned from corfu.i had mosquito bites,not itchy little red dots. now i started with white lumps, itchy, now red, delayed reaction? tia

Need more info: You need to see your family physician and/or a dermatologist. Hard to give you an accurate answer without examining you.

It's possible ...: ...but I think you first have to question whether the "itchy little red dots" were actually mosquito bites. Other kinds of bug bites, heat rash (miliaria) or even swimmer's itch caused by an allergic reaction to a waterborne parasite can produce red or white bumps. Use OTC cortisone cream for a day or two. If rash is progressing/not improving, seek medical eval. Good wishes:)