bomb pot river, to valuebet or not?

Clubgg bomb pot 8 handed
20NL
Only have 1 handhistory vs villain
Villain opens in UTG, Hero in Mp 3bets, he flats
Flop J43r, villain donks 1/2??????? Hero folds

Hero (MP+1): 117.95 BB
CO: 158.55 BB (VPIP: 40.00, PFR: 37.14, 3Bet Preflop: 28.57, Hands: 38)
BTN: 245.15 BB (VPIP: 24.49, PFR: 20.41, 3Bet Preflop: 25.00, Hands: 59)
SB: 81.7 BB (VPIP: 36.13, PFR: 5.20, 3Bet Preflop: 1.72, Hands: 430)
BB: 164.1 BB (VPIP: 12.24, PFR: 10.20, 3Bet Preflop: 18.18, Hands: 59)
UTG: 187.85 BB (VPIP: 42.86, PFR: 33.33, 3Bet Preflop: 0.00, Hands: 27)
UTG+1: 223.85 BB (VPIP: 22.73, PFR: 22.73, 3Bet Preflop: 16.67, Hands: 27)
MP: 91.5 BB (VPIP: 15.38, PFR: 7.69, 3Bet Preflop: 25.00, Hands: 16)

8 players post ante of 3.5 BB, SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 32 BB) Hero has 3♥ J♥

Flop: (32 BB, 2 players) 3♣ 9♣ 6♣

SB checks, BB checks, UTG checks, UTG+1 checks, MP checks, Hero checks, CO checks, BTN checks

Turn: (32 BB, 2 players) 3♦
SB checks, BB checks, UTG checks, UTG+1 bets 24 BB, fold, Hero calls 24 BB, fold, fold, fold, fold, fold

River: (80 BB, -4 players) 8♠
UTG+1 checks,
Hero????
We have about pot size bet left, how much are we betting if we are betting????
Or just check back???