There are dark spots on my hand..

After walking for several years for two hours each time, I developed dark spots on the back of my hands. ㅜㅜ

I applied sunscreen and wore a hat on my face...

Went to the dermatologist, 390,000 won..

But even if I do it, it might come back up again, so I'm 고민되네요..

I'm feeling stressed about fixing it and unsure whether I should do it or not.