I guess it wasn't entirely clear but she isn't balding due to any medical condition that causes her hair to fall out, rather she has trichotillomania which means she compulsively pulls out her hair but it still grows in normally.
A wig would be an awkward temporary solution since she'd need a bald cap to make it work and a hair transplant would be like getting a skin graft for a small rash that would clear up over time anyways