Hi, I Drank Half Of A Four Loko Last Night

Hi, I drank half of a Four Loko last night and when I woke up I had a rash on my lower abdomin, in between my thighs and on my butt, but no where else. The rash looks like sunburn, is warm to the touch but is not painful. This was also my first time drinking. Don't have any allergies that I know of. Nothing other than the drink was out of the ordinary.