Possible allergic reaction on kittens mouth

Hello! My kitten is less than a year old (probably about 8 months or so). Recently within the last week or so I have noticed this odd swelling on his lip. It's a little puffy. His activity is completely normal and he is eating as normal as a kitten should.

Here is the link to two images:

https://imgur.com/a/0MjUq4W

TIA!