It would be fine to use ice packs to decrease swelling after a Bellafill injection. Normally, any swelling after the injection should begin to improve after a few days.
Ice is certainly alright to use after Bellafill injections in the cheeks. I have found that some people get more swollen than others with Bellafill and it subsides in 3-5 days. Ice will help swelling and bruising for the first 24-48 hours.