I am scared to do injections under my eyes, so I am wondering if Radiesse in my cheeks will also help my eyes?

Radiesse (Calcium Hydroxyapatite) is an effective filler for deeper injection, and can certainly be useful for addressing cheek position and increasing fullness.  It has to be used carefully, and it shouldn't be injected under the eyelid, due to the thinness of the eyelid tissue, and thickness of the product.  However, when injected along the cheek bone, the tissue is often slightly lifted, which can decrease the appearance of under-eye hollowing.  If hollowing remains, I typically use a thin hyaluronic acid filler like Belotero or Restylane to further improve the appearance of the tear trough.  These are safer fillers for injection in that region.

I think Juvederm or Restylane (or other hyaluronic acid based filler) may be better for under the eyes. However, Radiesse is great for the cheeks.

RADIESSE® is a terrific filler, specifically because of its thick
consistency. This quality also makes it ideal for adding volume to the cheek
area with really beautiful, natural-looking results when you visit a skilled
injector. However, the very qualities that make RADIESSE® so great for other
areas are the same qualities that make it not the best choice under the eyes.
The skin around the eyes is very thin; not only can the RADIESSE® injections be
more apparent there, but the opacity of the substance may actually be visible
through the thin lower eye area skin. I’d recommend the cheek enhancement alone
to see how that affects the under eye area. If you are still unhappy, try a
different filler just under the eyes that is a bit more subtle.