It looks like he keeps re-injuring that finger and it's clearly affecting his game. We've seen Batum previously play with lingering injuries (ankle and shoulder on separate occasions IIRC) without taking the time for them to heal. He should strongly consider taking some time off from games and practice to let all that soft tissue heal.
The obvious problem is that he is absolutely essential to what the Blazers do on both ends. Even at 75% Batum is better than whoever the alternative is.
But here's the thing: if he doesn't find a way to heal, he may still be at 75% by the time the playoffs come around. Yes I'm speculating a bit on the nature of Batum's injury and I'm not a doctor, but he is visibly hurting out there and the notion that rest and avoiding re-aggravation can help injuries heal ... it's not rocket surgery.
The way I look at it, I'd rather lose some games in the regular season if it can ensure that Batum's hand will be fully healed at playoff time. That's better than winning more regular season games and having only a one-handed Nic in April. This team is suddenly good enough to start worrying about stuff like that. Greg Popovich, who is famous for resting players, even just preventatively, thinks like this every year.
An additional possible bonus: by forcing the team to find a way to play without Batum, there would be serious adjustment pains, but perhaps someone (Wright, Claver, Crabbe, ?) would find a way to step up his game with steady minutes. The team's attack would lose a dimension, but if they learn to play without Nic they will be that much deeper and multi-dimensional when he comes back. Basically, it could ultimately turn a team weakness into a less-weak weakness.
If he starts now, Batum could get a full two weeks off before the Wed Feb 5 game @NYK, and then be warmed up for the big matchup with Indy on Feb 7.