Nice looking stone... Ozukus can make very nice finishers... That looks like it's a surface inclusion and should lap out. You probably realize this but you're not done lapping at the point the second photo was taken. Don't hone before lapping is done... that will just end in frustration. You can get away with that in knife sharpening but not here.

You'll find honing razors is a different experience. There is a learning curve, but I don't think it's especially steep. Some of your knife sharpening knowledge will be useful, but not on methods of sharpening... you'll have to learn entirely different methods. Your knowledge will apply as general background on what the steel is doing and how the stones work...