I May Be Fired From Restaurant Job For Dyed Blonde Hair

Linear context: Mid October I had texted my General Manager if I could dye my hair blonde, they said it doesn’t go against any rules. That week I asked a “regular manager” about advice on how to dye my hair while they were sitting right next to the Director of Operations (basically biggest “Manager”), I got the advice to get it professionally done from both the regular manager and also the Director of Operations. I got it done shortly after and since I have dark hair it came out a little brassy. Since then I have been using purple shampoo and conditioner to eliminate the brass as well as getting it rebleached and retoned so it looks a lot better. Now in Mid December I have been told by other managers that the Director of Operations “needs” me to dye my hair back to a “natural color”. This just raises my concerns because there are multiple women with dyed hair who are not natural blondes and I feel like perhaps I am being singled out because I am a male. If I do indeed end up being terminated because I do not dye my hair back to a brown close to my natural hair color, would I have a case for unlawful termination/ discrimination/sexism? This is in Nashville Tennessee and i t is an at will employmentship, i had also asked HR about the rules and it’s directly stated in the handbook that hair must be “a natural color” but HR told me that, that is by manager’s discretion. Last thing im wondering is if I should record the conversation I plan on having with the Director or Operations or if that’s a big no no!