Hi Beth,
My reply is designed to help you and not insult in any way,
Not sure what Boots recruitment policy is and/or how flexible they are BUT I'm assuming this is a forward facing role. Whilst they wont actively discriminate they could select a candidate over you that they perceive to be more approachable / more professional in their presentation.
You won't like my answer but I wouldn't personally employ you with Blue hair and a ring through your nose and would consider you to look a mess and not the image i want to represent my brand in a public forward facing role, Sorry. I would select ANY candidate that turned up for the interview that was more presentable, over you.
That being said, depending on who interviews you and as i say Boots internal policy, if they are more flexible these days you might get away with the blue hair, maybe but, i would 100% recommend you remove the nose piercing.
Boots are sure to have a uniform/ dress code policy. My view is that Boots is a fairly corporate brand so they will likely have a certain perception/ guidelines of how their staff should present. I don't recall ever seeing someone serve me in Boots that had blue hair or a nose jewellery?
The only thing i could find on the internet was this:-
https://uk.indeed.com/cmp/Boots-Uk/faq/i-was-just-wondering-what-the-policy-is-on-coloured-hair-at-my-interview-i-was-told-that-if-i-have-been-successful-i-will-be-sent-through-the-uniform?quid=1dgq4d4oe9r5u800Not sure how much you want this job, but if you really want it, my advice would be to go to the interview looking as smart as you can be, ditch both the nose piercing and the blue hair. You could always die your hair back to blue later once you get the job IF its permitted in the uniform policy.
Good luck