how to get out of obs?

basically my obs is like literally next month and its really close to my chinese o level and i would very much rather be using these 5 days to study

thing is my parents already consented to obs and theyre not going to let me get out of it just cuz i dont wanna go so like💀

besides the o level thing i also just dont do well in environments like obs i literally get lightheaded and my vision starts going dark js from standing under the sun for too long but unfortunately i dont have a medical diagnosis that i can use

i was thinking of just getting an mc but im not sure if i need mc for all 5 days or just 1 or 2 days is enough? i lowk wanna like intentionally get myself so sick that i can get a 5 day mc so any ideas on how to do that would be appreciated 🥹​​​​​