Nice hand

I think villain played the hand fine 2, he was unlucky that you flopped a straight. On the flop he has about 32% equity against your hand.

He limped 55 I thouht it was a nono to limp this hand? If he raises im out immediatly and he dosnt lose 25.

Its ok to limp if someone else limped in front of you, pockets do well in multiway pots and with 2 limpers its likely that it will be a 3 or 4 way pot. The advantage of limping is that if someone raises you can still call. If you raise and get reraised, you have to fold it. The advantage of raising is that you can pick up the pot preflop or with a cbet on the flop. So its a trade off.

Obviously it didnt work out for him this time, but 90% of the time when he hits his set he will win the hand and with 3 or 4 players on the flop he will win a decent pot. Even this hand he had 32% to win, so he really only loses it 2 out of 3 times, so on the long term its not as bad as it looks