Did I oxidize my beer?

Okay, so on Feb 22nd i made my 2nd batch using my Coopers kit. About 6 days later I take of my Krausen collar, which I need to remove the lid to do.

Its still hanging out in its 12 degree Celsius bath, But about 5 days ago I get it in my head to dry hop, so I lift the lid just enough to shake in the pellets.

Now I am worried since I have a huge amount of headspace in the Coopers fermenter and I released whatever CO2 was in it, that I will have alot of oxidation.

Also, the beer I am making is a modified Coopers Lager. It was my intention to toss the whole fermenter in my fridge while I am away on Vacation for the next 3 weeks. Should I bottle it before I leave to save it from oxidizing, or should I give it the much favored Lager fridge time

Thanks!

CO2 is heavier than air, as long as you didn't agitate the airspace too much, the CO2 blanket should stay relatively intact.

You didn't hurt anything. It is much harder to oxidize your beer than that.

How else would you add dry hops. you are fine.