Your dermatologist is wrong. Nobody has a fluoride allergy/sensitivity, that whole perioral dermatitis thing was disproven years ago. You're probably reacting to the sodium lauryl sulfate. You can find many pastes without it, try this paste: https://www.amazon.com/Hello-Oral-Care-Sensitivity-Toothpaste/dp/B01N4IEXJK
It took me a month before I saw results. I use this stuff : https://www.amazon.com/dp/B01N4IEXJK/ref=cm_sw_r_cp_apa_fabc_Q0Z35HJ03YXJ4AYJSD14
What brand did you find?
(I don't know if Im allowed to post Amazon links - I'll remove it if I need to.)
I use this stuff because it cuts out a bunch of chemical irritants. https://www.amazon.com/dp/B01N4IEXJK/ref=cm_sw_r_cp_apa_fabc_5V5CT5NAFGQSVP4AXEFH
I use the Hello brand Sensitive version found here on Amazon.
I really love the Hello brand. I buy it on Amazon.
They have a bunch of varieties, with or without flouride, no SLS, all with xylitol. Good ones for kids too!
Looks like you found yourself in a pile of bullshit. Here, why not both? https://www.amazon.com/Hello-Oral-Care-Sensitivity-Toothpaste/dp/B01N4IEXJK?th=1