Is he hot or have a tempreture? flushed cheeks are a good sign of this, even if there is not any grizzles or discomfort...

Mj had red cheeks for ages before getting teeth.
I took it as a sign that something was moving in there. MJ had teeth on the move for about 3 months before he first one actually cut through. They do a lot of moving first.
Is he rubbing hus cheeks/mouth or touching his ears? its usually as sign that they are moving and there is some discomfort there.
I would second the paw paw ointment, MJ has terrible dribble rash and this helped better than anything else.
Although it will not take the red out of the cheek it its just increase blood flow (due to irritation of gums with teeth moving) but will help with any dryness or topical irritation.

If he doesnt seem bothered i wouldnt be too concerned.