Botox left dent in forehead - adding a filler left dent and bump what to do? (photos)

I had my second Botox treatment in December 2015. It was 30 units for my forehead lines .in August it was 45 units . A couple of weeks after this treatment I had a pretty significant dent in the middle of my forehead. Went back to my dermatologist and she said I needed a filler. After filler dent is still there...but now there is a dent with a bump on top of it. What should I do? Should I just let botox wear off and wait for filler to go away as well? Bump is most prevalent when I lift my eyebrows.