uneven gloss layers

Hi ,

I’ve stripped the handrail, however it’s also lifted some gloss from the spindles. There are layers and layers of gloss, so now there is a lip between the stripped gloss (it’s gone back to wood) and the existing layers of gloss. I don’t want to strip the spindles however would like a flush finish to regloss.
- Do I sand the lip and try to get it feathered the best I can ?
- is there some filler that I need to use to re level it ?

Thanks you . PS I’m new to DIY sorry I appear to ask daft questions