Some gyms have bars that are smooth in the middle and have no groves.

What I do is I find the bar in the gym that is worn down the most. Then it doesn't tear you up so much.

If I were you I would take enough time off the deads to let your shins heal. If this is not an option go out and get yourself a pair of shin guards (soccer player ones) even a pair of child ones will protect you ($5?)