How would I make a health bar fit within an odd shape?

[Silver_Wolf5874 (NotThatGuy)]

1. I am trying to create a healthbar that looks similar to this:
   

   

2. My healthbar looks like this, and I can’t fix it: (Specifically the left and right edges)
   

3. I have looked on the devforum, but I can’t find specifically what I need.

The frames are the edges of the healthbar.

Thank you in advance!