Random post but I just need some advice

I’m embarrassed to post this so that’s why I am anon

But I have been trying to get a dentist appt but I guess everywhere around me isn’t excepting new patients so I am resorting to asking online

But I have these translucent places on my teeth and white spots that make me so so self conscious

Does anyone know why that is? What causes that? Is it reversible? What can I do?

I brush 1-2 daily with crest 3-D white toothpaste and I use crest pro health mouthwash daily

I was wearing a retainer every night as well but I recently lost it so idk if wearing it can cause this?

I just don’t know but I hate it so much