Ahhhh....a long weekend in the sun! But too much sun can lead to heat or sunstroke. I suffered form this on a long weekend many, many years ago. My first trip to Lake Huron and for some reason I was totally unaware of the length of time I spent in the sun. Heat and Sun stroke can be very serious - even life threatening. It is important to stay hydrated, wear light clothing, and get your temerature down with gradualy cooling should you suffer form this condition. Medical attention should be sought.
For the minor variety there are several homeopathic remedies offer great help. Two of the most common ones are Belladonna and Glonoine. Choose the remedy which most accurately matches your symptoms.
Belladonna: burning skin - dry heat on head. Throbbing, bursting, hammering headache. Red face. Headache worse forlying flat but better for keeping still in a darkened room. Better for bending the head backwrds. Fever - heat alternatng with chills. Starring eyes - may be in a stupor. Dilated pupils.
Glonoine: Very similar to Belladonna. Red face. Heavy headed with dizziness, throbbing headache. Cannot bear ay het around head or having it covered. Dull and collapsed state. Better for cold applications and holding the head. Throbbing, bursting headache increases at sunrise, dereases at sunset.
Belladonna would have done the trick for me back then. I just wish I had known about Homeopathy then!