How any ccs of Belotero to tear troughs for optimal results?

The amount of filler needed to correct the tear trough is different from patient to patient. The safe way to avoid too much swelling is to inject 1cc at the time, because too many cc's in one time, gives you more swelling. Some patients with 1cc will have a full correction, but others may need 3 or 4cc, not just in the tear trough area, but also in the cheek area, to improve the contour of that area.

Belotero is one of the thinnest available fillers which means it spreads everywhere. Restylane lifts under eye hollows better and is more accurate while lasting longer. You can consider adding Restylane about 2 weeks after your initial treatment.Prp and microneedling will have very limited benefit to under eye shadows if any.

I wouldn't place more filler one day later.   Give it time and then consider it at 2 weeks.  Best of luck