If there is dissatisfaction with the results of a procedure, it can give your self-esteem a beating. The good news is the problem can probably be improved significantly. The bad news is that it may not be possible to restore your forehead 100% to its original appearance.
Injectables like Dysport or Botox could be viable to help lower the forehead back down, but it will be a temporary fix. Otherwise you can perform a second endoscopic procedure but again, restoring it 100% to where it was before may not be possible.
The best bet is to discuss all options with a surgeon experienced in forehead and endoscopic procedures, and go from there. Once you’ve had an exam and discussed all the options, you can decide on the least invasive yet most effective treatment action tailored to your needs.