"Bollocks," Snape spat. "'Just a slip'? By trying to talk down your fuckup, all you've managed to do is reinforce the blatantly obvious fact that you can't be trusted to manage your addiction. Very well," he growled, "You'll report to Healer Goldsmith every weekend, for a full physical. And if he finds so much as a hint of alcohol, narcotics, opiates, hallucinogens, stimulants, depressants or any other proscribed substances in your system, you will be expelled from this school so fast it will scramble what little is left of your brains.
Oh, and by the way?" Snape gave a truly evil smile, "In your case, 'proscribed substances' include makeup.