Kavod HaRav, Is there any reason flavored lip balm (or chap stick) would be acceptable year round or during pesach without proper supervision?
In principle lip balm does not require a hechsher, because it is not food and it is not suitable for consumption.
However, some have the custom to require supervision even for soap and the like (because sichah (smearing) can be considered as drinking), and therefore you can find many soaps and lip balms with supervision. This is not required however according to the strict halachah.
For lipstick, out of concern that the lipstick will become stuck to food and swallowed, and this is considered “achshevei” (giving it the importance of food), some are more particular. However, according to the strict halachah this is not considered “achshevei” because there is no intention to swallow the lipstick.
For flavored lipstick there is perhaps greater concern for “achshevei” (though in principle it appears that there remains no concern for swallowing), and one should be careful to use a product with supervision for Pesach.