Good question Marcello, yes if taken literally... "My head is blown" would not translate very well. If you're trying to communicate that something incredible happened, and you couldn't believe the impact it had upon you, you certainly could say, "It blew my mind" (past tense). Or like Steve wrote above, "My mind is blown" (present tense) or even... "It blew my mind". I hope this helps

"My mind is blown" or "that blew my mind!"