Just ensure it's clean up as you've done, ensure oil is at the right level and then just keep an eye on it, thats all you can do.
Unless it suddenly starts spitting it out then I can't see anything to worry about.
Worst case it'll be a weeping gasket anyway so no real biggy, may even be that the head gasket that was replaced hasn't seated tightly enough, but if you've checked it for weeps then it may not be that.
I assume you've checked all gasket joins for weeps.
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