When you drink too many cans or lager/ale over a few days, resulting in a sore and cracked upper lip.
Man 1: 'Alright mate, your lip looks a bit sore.'
Man 2: 'Yeah man, been at a festival all weekend drinking out of them cans, got proper bad can rash.'
by yerkshirelad June 17, 2015
Get the Can Rash mug.