Character acting as brush texture for terrain

Hello,

I'm new at using Unity and I'm trying to make a game where as you play, your character change his surrounding when he walk (overwrite texture).

I tried to search how to do that but there is only very few who talk about it and either it's too old to apply as a script or it's too much complicated and I don't know how to use it.

Mainly I just want my character to be the texture brush in the terrain editor, but in runtime.

It's seem like to be a very difficult matter but if someone somehow know how to do it, I would be really grateful.

I don't know if it's the right way to do things but I'm really desesperated.