Arizona, Security Guard - Can My Employer Force Me To Take Off My Face Mask If I Choose To Wear One?

Reposted because i didnt realize i couldnt put my company name in the title, sorry, fairly new to posting on reddit :(

(TLDR; piercings and tattoos are against policy, but my lip piercings are covered with a face mask that matches my uniform. guards with tattoos are allowed to wear arm covers, so why cant i wear a mask to cover them as well as my preference to wear it even if i didnt have piercings to prevent myself from getting sick??)

For context, I (24F) am a security guard in arizona. At my current post (lets call it "Business" for privacy reasons), the security lead of "Business" (not with my security company) is upset that I wear a face mask, and may try to force me not to wear it. Its a black cloth face mask covering my nose and mouth, always clean, well fit. Nothing offensive and it matches with my uniform.

I wear this mask both to cover my lip piercings and to not get sick as even without piercings, I would prefer to have one. Lots of people come to work sick and I catch it really easily. I don't have medical conditions requiring me to wear one, but it is my own health preference.

Now, in the Security Company Handbook, it does not say anything about not being allowed to wear a face mask. Only that they can make you wear one if you dont want to. In the "Business" handbook, it does not mention anything about masks, nor mention not being allowed to wear one. Face piercings are not allowed in either handbook, but they are covered anyways. Although it is understandable face piercings are not allowed, security guards with arm tattoos are permitted to wear black arm sleeves to cover them up. So, A. Why would they be allowed to cover up and its not against uniform policy and I cant, and B. Is it legal for them to force me not to wear a face mask in general for my own health preference?

Not only does it seem unreasonable, and frankly makes it feel slightly discriminatory, but I strongly feel like I have a right to wear one.

Could I be fired for this, or could this be something I could fight?

I appreciate any help, and thank you so much for any advice!

Location: Arizona