How can I treat sun damage to forearms?

I'm a 44 yo female & have hyper/hypopigmentation on my forearms. My skin pleats when I bend my arm (see pic). I also have crepey skin here and on my elbow. My skin tone seemed to diminish after I had laser hair removal. I started using Retin-A 0.1% on this area but it seemed to make it worse. I want to tighten the skin which seems to feel mushy (lost it's volume) (I haven't been dieting and am not menopausal). What would you suggest for tightening and sun damage repair? Thank you.