It's possibly a sign of lymphoedema, which can have a multitude of causes. While lymphoedema is primarily characterised by swelling, there can be other, less noticeable changes (such as skin colour) which indicate its presence. (When I attended the lymphoedema clinic at my local hospital, I was only aware of the problem being present in my left legs and foot but the nurse could see it on the right side too):
https://www.nhs.uk/conditions/lymphoedema/
It might also be linked to peripheral neuropathy:
https://www.nhs.uk/conditions/peripheral-neuropathy/
Either way, there's probably an underlying cause, so you need to seek a medical opinion in order to identify and treat that cause.