Treatment for dent in 5 year old's forehead?

If still evident at a year and bothering her then consider treatment.  Often times these decisions for treatment are best delayed until the child can weigh in on the decision.  These difficult situations are often rushed and driven by guilt ridden parents desperate for a quick fix.  Be patient.  

I suggest posting photos and making a formal consultation with a cosmetic dermatologist who has experience in treating scars.  Best, Dr. Emer.

Thanks for question. I would wait at last a year to see how that area evolves. I have a feeling it will just resolve on its own. If it remains noticeable, then start process of seeing and getting consults after that.  Depending on what it looks like there is probably many options you will have.

I would wait a full year in a child before deciding to treat traumatically induced forehead/skull indentations. They may go on to improve with more healing time, or not, but in a growing child what one sees today may change later. Persistent and aesthetically bothersome forehead indentations may be eventually treated by fat or Acell injections since they are soft tissue based and not a bone deformity.