You may massage the area injected with a hyaluronic acid filler if you see a nodule or bump.
In my view, there is no need to massage an area injected with hyaluronic acid unless you see or feel a nodule. The filler is somewhat malleable for a few weeks after you're injected. So if you're inadvertently overcorrected and see a nodule, massage may help to smooth the area.
Regards from NJ: