Tiger balm is excellent, it really works. You can get it on Ebay. i have used it during trips to India and it is the only thing that works for me, I draw midges for miles! An antihistamine will also help, as it is histamine that causes the irritation.
with 300 bites you must be in a bad way, i have a bad reaction to some bites, most are just annoying but some cause a really bad reaction with me. ended up in casualty once, my GP was concerned at the speed of the reaction and did not believe it was midge bites!