Openly wearing a bra to school would have been a dramatic paradigm shift, but on the other hand I was constantly told every day in school I needed a bra so it was not like it was a secret. My breasts were often on full display on the skins teem during physical education.
From what I've read elsewhere on the forum I don't think you are the only one to have been forcibly forced to flaunt yourself on the skins team. It was never a problem for me, I was a normal teenager I guess, but I just wonder - and this applies to anyone - if you were on the skins team but still wore a bra, would the teasing and bullying have been worse?
Most likely any consideration of wearing a bra to school would have required some sort of exemption from gym classes. Besides being on a skins teem with a bra on, simply changing into gym cloths in a bra would not likely work well. (Even though the entire class was accustom to seeing my bare breasts every time I changed or was on the skins teem). A bra would likely be visible through the required gym shirt in our classes as well.
With irony, I remember being on the skins teem in a mixed gym event, where the few girls who were also on the "skins" teem were obviously keeping there gym shirt on. And yes, I was yet again called out for needing a bra.
In some ways, wearing a bra to school under the right cloths would feel more safe than exposing breasts in gym. It may not even be obvious right away if one was wearing a bra given that everyone already was aware of my breasts.
No easy solution; even if you accept your breasts and the comfort of wearing a bra, it is not easy to fit in particularly as a teen.