Forgot to Purge Keg!!

I filled up my corny to about 1inch below the inlet tube, put the lid lid on and forced carb'ed the keg @ 30psi for about 2-3 min. I just realized that I forgot to purge the keg first to get rid of the O2.
I guess it is too late now, the O2 should be mixed with the beer.
Has anyone else done this without suffering from a cardboard tasting beer?
Is there a remedy?

Sorry wrong forum, reposted in bottling/kegging.

You are likely to be just fine. Very little O2 was in there. It will take some time for the cardboard to come around if at all. RDWHAHB

When I first started kegging i did not know you should purge the keg. I did not have a problem on those first 2.