I wouldn't worry too much about this.
I did the same thing once and it occurred to me to put in an oxygen scavenger (ascorbic acid) to take care of it, but SWMBO came along, handed me a cold pint and I forgot to do it. Long story short, there wasn't any problem with that keg when I got around to drinking it.
We cannot defend freedom abroad by deserting it at home. Edward R. Murrow