Hi,
If he's completely unknown, why are you 3-betting QJs in position?

Now you're in a bloated pot with TPGK on a kinda drawy flop, without any idea whether this guy can show up with Q2-QA or just QA in his 3bet-calling range, if he's simply going to check/raise monsters or virtually any pair and so on. So I'd start by just calling preflop in position.
As played either bet/fold and hate it when he raises or check it back. We're not really afraid of much, any overcard gives us a draw with our TPGK and what we're getting value from by betting is really unclear. Any pp is probably going to fold, he likely doesn't have many Tx hands, even if he's fishy he probably doesn't show up with too many worse Qx either.
Hope it helps.