catch (one) on the raw
To do or say something (such as mentioning a sensitive topic) that causes one to feel angry, agitated, or self-conscious; to touch a nerve. Primarily heard in UK. I accidentally caught Vanessa on the raw by mentioning her new haircut—apparently, she's really unhappy with it. Your column must have caught the MP on the raw, because we've been served with a defamation lawsuit from his office. I could tell she was touching Jack on the raw when she brought up his former employer.
catch/touch somebody on the ˈraw
(British English) upset somebody by reminding them of something they are particularly sensitive about: She touched him on the raw by criticizing his driving.