Hi there! Those dents are due to very active frowning muscles. I recommend you start by treating the frown muscles with Botox every 3 months. Be consistent and try that several times. Once you are continuously relaxing those muscles with Botox, they should soften and flatten a bit, making those dents less noticeable. Only if they are still there and still bother you, then you try filler. The reason why filler isn't the first choice is that this area (the glabella) is a "high risk" area to treat with filler due to the risk of blocking a blood vessel ("vascular occlusion") and rarely blindness can occur. Since the dent is due to your active frowning muscles, it's best to soften the muscles with Botox before turning to filler.