My stye is on the inside of my eyelid not on the outside. In this case, how do I use the teabag method?

Limited effectivenes. You can still try the teabag method on your closed eyelid; its effect will be limited. A better method is to apply a hot wet compress to the closed eyelid twice a day. If that doesn't work, see an ophthalmologist, who may prescribe an antibiotic drop, ointment, and/or pill, and/or may drain the stye in the office if you agree to it.
Avoid teabags. The tannic acid in the tea can cause irritation to the eye and the tea can stain the skin, giving you dark 'racoon eyes'. Instead, use a rolled facecloth soaked in hot tap water (comfortable shower hot, not scalding) over the closed eyes. The heat will get to the internal bump if you hold it there for about 3-5 minutes.