Teething Issue?

Hello. My son is 33 weeks now and for the past 1 month, he has problems finishing his milk and now he doesn't even want to take from the bottle. It started with him able to drink about half his milk normally and needing to distract him to finish the other half. Now once the nipple touches his mouth, he will turn his head away. Currently feeding him using spoon. Recently a very small part of his teeth has came out. Is this because due to teething?