You can overfeed nems, how long has it been in and at what frequency did you feed. Also what did you feed, powder, live phyto, preserved phyto, fish food?
Also I'm certainly no expert but it looks fairly pale, may have lost a large amount of its Zooxanthellae if its completely bleached It may be too far gone.
Check out this article about nem bleaching and recovery, It suggests that if the nem has an anemonefish caring for it has a higher recovery rate than those without. https://www.nature.com/articles/s41598-020-75585-6
Fed it powder. Had it 4 days fed it 2x just a little squirt.. he moved again last night and as I'm typing right now he just let himself go from the rock he was on. I bought a frag of finger leather and it had 2 anemones on it. The other one is doing good. This one hasn't really changed