Uneven window sill

[inspecta72]

Hi, I was really hoping somebody could help me with my first post! I am currently having to strip paint from and sand-down all woodwork within a newly purchased house. I have been using a heat gun and unfortunately whilst stripping a wooden window sill a long strip of wood - approx. 2mm deep - was peeled along with the paint. I then had two options available, fill the hole/strip with filler and then sand over or sand the area around the hole to 'blend' it in. I chose the worst of the two options and attempted to sand-in the hole - thus creating a narrowing of the sill where too much wood has been removed. My question is, am I able to use wood filler or some other leveling compound to flush the surface of the sill? I appreciate that filler is used predominently for filling holes and cracks but am I also able to use it to raise the surface of the sill?

I have searched extensively for an answer to this question to no avail and so any help would be greatly appreciated.

Steve.