Soss,

SB probably doesn't have a 3 vs pf raiser in a protected pot. You are most likely against a smaller pocket pair. I like reraising the turn rather than waiting for the river since an overcard could induce him to check, and he may have 44 or 66 with straight outs that need to be charged. I guess I would fold to a 4 bet but I never seem to do that in the heat of battle...