dog bitten by tick - what to watch for at site?

I use flea & tick treatment, but my dog got bitten by a tick. I am going to have the yard treated to help in the future. My concern is that the tick was on his face pretty close to his eye and he has a bump where he was bitten. We cleaned the area.

I'm pretty sure I got the entire tick off of him (from what I could glean off the internet). I am hopeful that because the bite was in a sensitive area that is why it looks as it does. But I was wondering if anyone with tick bite experience could clue me in as to what to watch for so I can get him to the vet if something is wrong.

He is his usual playful self, eating fine, going potty as normal, so I'm not worried on that front. I've just never had a dog bitten by a tick before and am concerned I might overlook something that someone with more experience in this area would know is a sign of trouble.

Your guidance is greatly appreciated.

Thanks!