I think the main problem is that Differin makes you more sensitive to the sun. So, if you choose to continue using it, you might want to start wearing a brimmed hat.

Yes do wear a hat while outside.I've been on differin and doxy for about 6-8 months.Made the mistake of going out in the sun without protection.Bad idea,my chin where i use the differin,got so burnt it took my skin a week to recover.Never gonna do that again.In the morning i wash with an acne wash,at night i wash with an acne wash and then apply differin.Take care.:)