First, we hope you never need to use an Epipen on your child because they can’t breathe, but having done this twice myself, I’m grateful for their life-saving abilities and would use one in a heartbeat if my son is having trouble breathing. Please see When should you use an Epipen? if you’re unsure about when to use it.
This will be a super stressful time, you likely won’t have a chance to check expiration dates, you won’t be able to really see if the Epipen solution is cloudy or murky because everything will seem like it’s cloudy and murky. You’ll just wan’t to do it quick and right. This video explains the process in more clarity than words ever could: