Lip shadow/melasma?

[lips2024]

Noticed this shadow over the past week, wonder if it's melasma or something else and how I can get rid!
I use tretinoin already

Tranexamic acid 500mg prescribed from a Dr
Sunscreen daily esp if using tret
Azerlaic acid 10% topical serum

SPF tick
Az acid (I can't spell this late!) is in my prescription too

What does the TX acid do? I had that for periods but couldn't tolerate it

Google tx for melasma only because it's long and clever and I don't want any to explain wrongly.
I had a very obvious melasma three months ago, forehead and mirroring pattern , by my eye socket, cheek and a very faint mouth shadow.
I also had very short hair so there basically no way of "masking"" it.
Three months in, you can hardly see it, apart from a small "shadow " by my hairline which isn't that obvious.
I can't believe the difference!
I use azelaic acid separate and in an eve
& Vit c moisturiser

About three months ago and this morning ( I don't live in a cave!) very dark photos, change of phone and poor lighting