Inquiry on treatment and management of 'dark spots' on the face and back of the hands

I'm planning to visit with my parents.

Recently, the dark spots (seborrheic keratosis) that have been appearing one by one on my parents' faces and the backs of their hands have become darker and thicker, and they feel depressed every time they look in the mirror.
I would like to treat you as a child, but I am worried that it might irritate your elderly skin too much, so I am leaving a consultation message in advance.

I've heard that the treatment for freckles is different from that for other freckles. I'm curious about the freckle removal procedure and whether it's usually possible to completely remove freckles after just one session.
Also, I would appreciate it if you could recommend some whitening and regenerative ampoule ingredients that I can apply at home to help my skin regenerate without leaving scars after the procedure.