blow by in 225, what does that mean exactly?

So I can somewhat find my way around a car, but i've still got a lot learn. I have had my car back on the road for a little over a month now, and Ive encountered a few issues and managed to work them all out. It runs super quiet and smooth and is a pleasure to drive (now that it isn't stalling at every intersection). Now, I took it on its first long drive, about 10 hours within a day. My old mechanic friend went to take a look at the car, and there and behold there is oil in the air filter. For the month I drove it before, it never happened. I watched temps closely in the car, it never overheated, it got warmer on some of the canyon inclines, but I kept it cooled off. Previous to getting it on the road, I did the compression test and all resulted within good standards.

So I guess what im wanting to know is, what should I be expecting? Does this mean my engine is going to go soon? Is there anything I can do to lengthen the time before that happens, and are there things I should be watching for as warning signs etc?

Thanks for helping this naive car enthusiast out :)