before this pandemic I wore a mask when Im in public transportation to protect my face from dirts, pollution & sun exposure, it helps a lot to reduce the appearance of acne.
but due this pandemic, I wear mask for a long time. from my experience, I noticed that cloth mask & wearing make up under the mask are the triggers of maskne.
double masking with medical mask (not sure that all of them are medical mask, but you certainly know that the 3ply mask which are generally blue or green) inside & the cloth mask outside are quite helpful to reduce maskne. (I'm double masking also for double protection as the positive rate increased here).
that kind of masks that have spaces such as kf 94 or 95 are also didn't cause maskne as much as I wore cloth mask. I haven't tried mask bracket as afrynkhyra suggested, but I think it's a good idea! (I'm thinking to try it too soon bcs maskne is quite frustrating for me).
other than that, I use minimal make up under the mask. I usually only go out with sunscreen or loose powder (since I'm an oily).
then, make sure to double cleanse when you get home. exfoliator and clay mask are quite helpful to clean all the dirts that's clogged my pores. if maskne still get there, look for soothing products like those containing centella, calendula, mugwort, heartleaf, moringa, etc.
may it helps you:)