What are these bony knots on my forehead? (Photo)

It's hard to tell from the one photo, but if these bumps are from irregularities in you skull, or even if they are soft tissue bumps, the best approach would be to fill around them to raise the area around them. Your best option would be to have an experienced doctor fill the forehead with your own fat.

The photo is a little unclear and your forehead is not visible in entirety but it looks like you have volume loss of fat and probably muscle and even possibly bone in that area below the area of which you speak. Filler with or without PRP can be carefully injected there but seek someone with experience to avoid pitfalls of compromising blood supply.