I have noticed recently that that I have had an increased number of coughing fits which have lead to vomiting when I've been wearing a face covering for work even though I am exempt it has happened three out of my last four shifts and twice as happened two days in a row.
Increased coughing and vomiting - Asthma Community ...
Increased coughing and vomiting
Is it a fabric mask? If so, are you washing it in a non-scented detergent? I'd recommend a liquid rather than a powder (e.g. BioD), so it has less chance of getting a powdery residue left behind, which may aggravate your breathing. Make sure it's not left anywhere particularly dusty to dry. Once dry, place it in a clean bag that you can zip/seal to minimise irritating particles that way too. Hope this may help. You could also change your mask more often during your shift, so have a few washables on the go at once. And if none of this helps, perhaps a shield may suit you better? The other thing to note, is if this is only just happening and you've been wearing masks up to this point, it may not be the mask so it's probably worth speaking to your doctor or one of the asthma nurses to see if you need a check-up.