In pain after dentist visit?!

So, today I went to the dentist to go get a cavity filly on my lower left back tooth.
Well, after 50 minutes of injecting me to get numb, I could not get "officially" numb in the mouth.
By that, I could not get numb on my lower lip. My tongue and left side was numb, but not my lip.
So, I was told I would be sent home and we would have to try again next time.

He injected me three times, in three different ways.
He gave me all the numb medication he could give me, and I never got numb.
Is this strange or what? I don't know what to believe. Has anyone heard of this before?

Well, it's been 3 hours at least since leaving the dentist with a numb mouth,
and I took a nap when I got home just to ease off to the awkwardness of the numbness.
I woke up about 2o minutes ago, and my mouth has waken up for sure now.
Nothing feels funny, but I will admit that on the upper left, back side of my mouth really hurts.
Not to a pain where it's unruly unbearable, but it's bothersome and painful whenever I try
chewing something or even trying to eat soup.
Even eating one simple grape is quite bit of pain,
and sucking a liquid is just very irritating and hard to do.

I took tylenol and it's not really working.
It feels swollen still.
Even my throat is phlegmy and I have a bit of a irritating cough.

What could be wrong?
Is my mouth still recovering or could something be wrong?

Please, I need help.
I would like to know what's going on here with all this mess.

Thanks.