That's a nice looking Jarlsberg. And yes, the swiss types are supposed to swell as the eyes form. Let it go next time. You need to worry about swelling if you haven't added PS as a culture. Some others will produce a bit of CO2, and cause a wee bit of expansion (Flora Danica produces a bit of gas), but if it expands like a football, well, that's good if you added PS, not so good otherwise. In your case, it was good! Well done and a cheese to you.