Large temple indent from Radiesse. How can I fix this? (Photo)

At least from the photo provided, it appears that the "dent" is likely to be the result of a larger than necessary mound of Radiesse to its side, essentially creating a valley to the side of a mountain.
If this is indeed so, then an attempt to flatten the "mountain" would minimize the appearance of the depression to its side and create a smoother transition between both areas.
The original advantage of Radiesse years ago was that its effects lasted around two years, which was considerably longer than what could be achieved with the earlier available HA fillers. (For some time already, we now have available more robust HA volumzing and lifting fillers whose results may last up to two years.) The problem with Radiesse, and why I stopped injecting it quite a few years ago, is that, unlike with HA fillers, there is no enzyme to dissolve it should adverse reactions arise.
Simply waiting for the Radiesse to be metabolized away, which may take up to a couple of years, is of course one option.
Alternatively, physically attempting to break up the Radiesse with subcision accompanied by the use of saline injections (and if necessary with the addition of a small amount of steroid) can be considered to attempt to thin the unwanted mound of Radiesse.
I would be concerned about injecting HA filler in the "dent," as this may simply create an overall, overly bulky appearance to the entire temple.
You would be wise to consult with an experienced, expert board certified cosmetic dermatologist filler injection expert. Hope this helps and best of luck.

Thank you for sharing your concern and photo. Radiesse is a calcium hydroxyapatite–based filler, and placement in the temple requires careful technique and depth. When filler is injected too superficially in this area, it can sometimes lead to irregularities, contour indentations, or uneven volume distribution, as you’re describing.

Management options typically include:

Hyaluronic acid–based filler correction: In some cases, additional filler (preferably hyaluronic acid, which is reversible) can be carefully placed in the area to restore a smoother contour.

Steroid or saline injections: Rarely, if there is an inflammatory response or nodularity, these may help, but this is less common in simple contour issues.

Time: Some irregularities may improve over time as the product integrates, but Radiesse does not dissolve with hyaluronidase since it is not a hyaluronic acid filler.

Expert revision: A skilled injector experienced with temple anatomy can often improve the appearance through careful, deeper placement of a different filler.

So, the indent is most likely due to superficial placement or inadequate volume distribution. The correction usually involves expert use of another filler rather than dissolving.