Exfoliants and lightening agents prior to IPL?

I have PIH and use AHA/Differin w/ improvement on a regular basis. I tried 4% hydroquinone w/ minimal success (x3 months) and suggested an IPL. Should I stop using Differin/other exfoliants prior to my session and for how long? Also, I understand HQ “preps” the skin and can be good before an IPL. To my knowledge, HQ should be used in cycles (3 months on and 3 months off) to prevent paradoxal hyperpigmentation. I have not used HQ for x2 months, should I start using it again prior to my session?