In the final scene of GS, Harry says she can't screw with his head. Technically, she never acknowledges that. So its debatable whether she agreed to it or not.
I don't doubt that she may have coerced Lash (assuming that's the parasite, insert your own name if you believe otherwise) to react to a few specific things re: mind control, but I really doubt Mab's actively screwing with his head these days, agreement or not. She put a lot of work into getting Harry
because he's Harry. The end of CD proves that. I think any other mortal who pulled a stunt like Harry did at the very end with her would be wishing they were dead right now. She wants Harry Dresden. Not some patchwork mental zombie version of him.
Her manipulation re: the blasting rod could have been solved by a conversation with him instead, maybe, but her reasons were totally sound.
What things does she need to hide from him these days?