It is common and expected to get swelling within the first month after hyaluronic acid filler treatment, which could be exacerbated by lack of sleep, stress, or salty diet, but it is unusual to experience chronic recurrent swelling beyond a month. In addition, some people do tend to build up head and neck fluid overnight more than others, esp. if premenstrual, so propping up on an extra pillow or two while sleeping should help prevent that.
If you have noticed a trend with the swelling of the product and don't like it, avoid those activities. Some people are prone to more swelling than others.
Ensure you are sleeping with your head slightly elevated and apply cold compresses when possible to bring the swelling down.
All the Best.