does Oxycontin have a physical effect on appearance?

For acute effects (i.e. take it and an hour later you look different) you might have a pale, whitish pallor, look drowsy/tired, and/or have small, pin-point pupils. Effects would go up with dosage.

For chronic, long term effects, it really depends on how hard the person's been hitting the Oxy. If it's under medical supervision and for legitimate purposes, the worst effect might be a little weight loss. If it's in gross excess and over a long period of time, you'd see weight loss plus the impact of a lack of personal hygiene - bad teeth, bad skin, just generally uncared for appearance.

palor, dilated pupils, skinny from lack of eating