I can't get rid of my pregnancy mask, from 2 years ago- What can I do?

To help treat melasma (mask of pregnancy) you need to use a good sunblock. Also, try looking out for a skin lightening product.
Remember to apply the skin lightener to the problem area.
There's many out there and it can get confusing what to use. So have a good read through this thread and hope it helps you decide what to use.
https://www.askmehelpdesk.com/skin-lightening/skin-lightening-frequently-asked-questions-190905.html