Why are there fluctuations with my dermal filler results?

Hello, I'm a young male. Dermal fillers in jawline and cheeks look good on some days but flat, deflated on others? I had fillers (8ml Juvederm Voluma) 6 mths ago. The first three weeks I looked incredible. Nowadays, I still look good, but the filler has diminished ~20%, so I'm just not as striking as I was. What I've also noticed is my face fluctuates a lot. One week I'll look handsome and fresh, and the next week I'll look much worse. It's frustrating. After shaving I look good bc of massage effect I guess. Why does this happen, and how can I maintain top aesthetics? Thank you.