which acid would you recommend?

U could basically use any other acids as well like aha/bha , vitamin c & niacimamide to treat hyperpigmentation ,blackheads and acne. Just make sure not to use these acids in the same routine them it shld be fine !! ☺️☺️👍🏻

Do u use tretinoin as spot treatment? I'm not sure its safety or not using acid and tretinoin on the same routine. But if u wanna try, u can buy paula's choice bha. Or for less gentle u can try cosrx bha toner.

You can try aha bha but in separate routine

I would stick to tretinoin. It is very effective when it comes to hyperpigmentation, blackheads and acne. Just give it some time.

If you're just starting with tret stick with it first bcz it's a strong ingredient. You might damage your skin barrier if you try to add acids too early. But if you really want you can try AHA or BHA. For me personally i am also a tretinoin user for about 4months already. But i only use it every other day so that i can still enjoy some acids like BHA. My routine looks like this: Tretinoin night Barrier repair night (means no actives just soothing and barrier care products) Tretinoin night BHA night Tretinoin night Barrier repair night Tretinoin night BHA night and so on Hope it helps :)