If it persists for more than a day and/or worsens seek medical attention ASAP. Hopefully it will subside; at least it is resolving.
Wow, that is some heck of a slap from a 2 year old; strong.
This happened this afternoon, when my 2yo son slapped me on my left ear. It has reduced a little, but was unbarable when it happened. It has been 5hrs now.
How long have you had this?
I would recommend getting imaging done, i.e. CT and an ENT consult.
I sure hope it goes away for your sake, but I can't say it won't