Suddenly appearing dark spots on the skin? How to get rid of them.

I thought it was melasma, but after looking it up, I found out it's actually lentigo. Can this be removed with a laser? I've heard it spreads if left alone, so I feel like I need to get rid of it, but my skin is very sensitive... I get seborrheic dermatitis and contact dermatitis easily, so I'm wondering if it's even safe to get a laser on my skin. The dermatologist I go to for Botox didn't seem to take it seriously, so I can't bring myself to ask them anymore. Please give me some advice if you have sensitive skin but have successfully handled laser treatments like this.