No, do not alter your MA state income.
Actually, I would expect that California is adding your post-tax HSA contribution in the additions part of the CA return (thus increasing CA state income).
If so, and if you made the contribution to the HSA only in MA, then you will need to add a subtraction to the CA return, listed as "Adjustment for non-California HSA contribution" (but only if you find that California added your post-tax amount back to CA income).
