word choice

"That hurts" is the present tense, and "That hurt" the past, so in theory there's a clear difference. In practice, of course, anything that hurts now (eg a slap in the face) did hurt when it happened; and if it happened recently enough for "That hurt" to be relevant it's probably still hurting. But it is better to decide which you meant, and then use the correct form: clear language goes with clear thought.