Hydroquinone. Hydroquinone and tetronin?

Hello I am 23 yrs male and I am on acne treatment, So I am currently using ointments of Tetrinoin 0.05 at night and hydroquinone 2% in morning, Since its summer time sun is on its peak, I wanted to know how can I prevent sun damage, can I use sunscreen after applying hydroquinone, if yes the what time gap should I keep between hydroquinone and sunscreen? I also wanted to know I have uneven skin color of my hands and feet can I use hydroquinone in my hands and feet too, should I increase hydroquinone concentration for hand and feet or same 2% would work for both face and body, and how do I apply sunscreen after applying hydroquinone on body, what time gap should I keep between the too, and how often should I re-apply sunscreen if working outdoors in day time. BTW I like to use ISDIN FOTOPROTECTOR water based Sunscreen, would that be safe with hydroquinone and tetronin? I request to please answer me without suggesting private consultation, Thankyou.