I had a subq injection thurs and think there might have been some air left in the syringe. i feel fine but how long would air embolism symptoms take?

You can't get an air: embolism with a sub-q injection.

You're safe: An air embolism needs to go directly into your vein to cause you harm. A tiny bit of air in the subcutaneous tissue is completely harmless. An air embolus would also affect you instantly. You can get some rest now and stop worrying.

Air in syringe: The small amount of air that would be in a syringe for a subcutaneous injection is not concerning. It has likely been absorbed by now. An air embolism comes from air injected into a blood vessel, not body tissue. You have no worries