a touch of the sun
1. A mild tan or sunburn. Looks like you got a touch of the sun out in the garden. You should really wear sunblock next time.
2. A mild attack of sunstroke, especially sweating, headache, fever, and delirium. I kept toiling away at the machine, not realizing that I was suffering from a touch of the sun and hadn't been able to think straight for over an hour.