Newcastle were beaten 1-0 on Saturday via Danny Welbeck's winner for the Seagulls.
Howe said afterwards: "I thought it was a good performance for the majority. We conceded with the first shot they had in the game. It's one of those moments where you go 'that sums football up'. That can happen sometimes when you're so dominant. One lapse in concentration cost us.
"I didn't feel we needed to totally rip up what we were doing. A goal looked like it was coming. The last 20 minutes was frustrating as we didn't put pressure on their goal. Credit to Brighton to the way we defended, but we're frustrated.
"We're going through a phase where we're not scoring, but the positive is we're creating chances.
"We can't feel sorry for ourselves, it's back to hard work on the training pitch."