Despite creating some good chances at the Riverside Stadium, the Cherries fell to a 2-0 defeat - their first reverse in five Premier League outings.
And Howe could not hide his disappointment at a result which he felt was self-inflicted.
"Whenever you get beaten you have to give the opposition credit, but from our perspective we certainly have to look at ourselves and take the blame," he said.
"We weren't as we have been in recent weeks.
"As a collective, from start to finish, we weren't where we needed to be, and that is hugely frustrating because today was a great opportunity for us.
"Both with and without the ball we weren't great.
"We moved the ball slowly, which is really unlike us. We didn't have our usual zip, even though it was a lovely surface to play on.
"And our decision-making around the box was disappointing - we were shooting our way from silly distances and not working our way better towards their goal.
"Out of possession we didn't have our aggressive pressing which we have seen in recent weeks.
"We were a yard off where we have been and ultimately that had a big bearing on the game."
Gaston Ramirez opened the scoring for a Boro with an individual effort as the hosts counter-attacked from a Bournemouth corner, and Stuart Downing doubled their advantage early in the second half with a close-range finish.
And Howe hopes the Cherries can learn from their mistakes as they get set to entertain bottom side Sunderland next weekend.
"We made so many bad decisions from that corner coming into the box, so we only have ourselves to blame from that perspective.
"And the second was frustrating because I thought we could have done a lot better in that situation.
"It's a lesson learned for us today and possibly an experience we needed to go through.
"We're not quite as good as we think we are, and we have to go back and work extremely hard to get anything in this league."
Late on, having already used all three substitutes, Andrew Surman limped off, leaving the Cherries down to ten men.
And the boss offered an update on the midfielder's fitness.
"It looks like a hamstring but I don't know how serious it is," continued Howe.
"He's gone for a long sprint on the counter-attack with Negredo and it looks like he's just tweaked something."