Shrinking my hat?

I just made a hat out of Cascade 220 Superwash, but it’s just a little big and baggy all around, and a tad too tall (this is due to the fact that I didn’t use the recommended yarn or the correct weight of yarn :doh: ) Since it’s washable wool, is there a way I could wash it and shrink it? I’m still afraid it will felt, even though it’s superwash. Thanks! 8)

I’ve heard that Cascade 220 Superwash actually blooms and grows quite a bit when you wash it…so washing it might have the opposite effect. :pout: