Which percentage of tretinoin do i need based on my skin?

[swspbdttli]

I have big pores,oily face,acne,blackheads and some closed comedones. Its not that bad with the acnes so im not sure which percentage should i use for the first time. Since dermatologist in my place rips off money for no reason i wanted to ask it here. Help please

I got the other things done like drink water guthealth, do this not that.

This is before washing my face so i look like this most of the time