What is a way to heal scars on babys forehead?

They will improve. Scars are permanent but almost all fade with time. This process takes longer in babies than in adults because their healing processes are more robust. Protect the scars from sunlight while there is any pink left in them; they will burn easily and, if tanned, may be tanned permanently. I would not expect the scar to assume its final form until the age of 4-5. Do not rush into scar revision.