Poker Stars, $0.02/$0.05 Pot Limit Omaha Cash, 6 Players
CO: $4.50 (90 bb)
BTN: $9.59 (191.8 bb)
Hero (SB): $12.50 (250 bb)
BB: $5.91 (118.2 bb)
UTG: $5.99 (119.8 bb)
MP: $4.37 (87.4 bb)
Preflop: Hero is SB with J♥ 5♣ 5♠ J♦
UTG raises to $0.17, MP folds, CO calls $0.17, BTN calls $0.17, Hero calls $0.15, BB folds
Flop: ($0.73) 5♥ 4♠ 2♥ (4 players)
Hero bets $0.60, UTG raises to $2.50, 3 folds
Is this a place to fold top set?
That's the problem with donking out into the field, you've isolated yourself against anyone with a straight or a strong draw like Q :diamond:8 :heart:7 :diamond:6 
As played, all you can do here is fold. I would much prefer to see you check/call this flop as there are tons of bad turn cards for you (8/7/6/3/A/any heart). This also gives people a chance to bluff you on the flop which they can't do if you donk out strong like this.
I don't see anyone playing 44 or 22 so you pretty much have to fold to the UTG raise.
