Here's a suggestion. Take a small brush and just barely touch the inner canthus area (tearduct) with cad red light straight from the tube. Right where the eyeball meets the skin at the inner corner. This is best done while the paint is still wet. Kinda gives the eye depth and defines that anatomy of the eye better. Don't use much, just a very small dab'll do ya. I mean barely any at all. Might try that on the next portrait.
Nicely done!
Les