UTG limps and I raise to $45 on the button with black KK.
UTG calls with $1200 behind and I cover.
He's newish to the table and I have no read.
Flop , pot $90.
He check-calls $90.
Turn , pot $270.
He checks, I bet $240, he check-raises to $620 with ~$500 left behind.
What do I do?