I ate before dental injection wore off... will this cause any issues?

It shouldn't...: Unless you've bitten your tongue, cheek, or choked.

Dental trauma: A patient can eat soon after dental treatment, but should always ask his/her dentist the approximate time to eat and drink. Dentists use different local anesthetics, whereas some wear off quicker than others. Local anesthetics that may last longer and cause longer numbness may make it difficult to feel when you are chewing. Therefore you are at greater risk of biting your lip, cheek or tongue.

No: Generally no but if you had oral surgery or a filling done you should tread lightly. Anesthetic generally wears off in 1-3 hrs with operative (filling) work & oral surgery (6-8 hrs if certain long a acting anesthetic is used in oral surgery cases). Just stick to softer foods till it wears off & you will be fine

Not recommended: You want to wait until the anesthetic completely wears off before eating, so you won't accidentally bite your cheek, lip and cause a trauma.

Eating after: Generally, it's advisable to wait until the anesthesia starts to wear off, usually about two hours. This is especially true if your lower jaw is numb, as it very easy to bite your lip, tongue or inner cheek and traumatize the tissue.