Adopted reactive lab hurt my 3 yo pug

My husband and adopted a retriever mix lab/golden around 1-2 months ago. We already have a 3 yo pug that has been with me since he was 2 months. He doenst really care for her he just minds his business but she likes to go after him and bother him, at first she was very quiet and thsi behavior wasn’t an issue. We originally thought she was playing but I didn’t like how she was going for his neck… he didn’t really get aggressive back unless she was actually bothering him and even still he’d just snarl nothing else. Fast forward a month she starts getting more comfortable and starting breaking and chewing things around the house (she’s a year already) again I was like well I’ll just be patient she’s new she might be getting adjusted.. fast forward again to a week or two ago she sees someone outside and starts barking, then turns to my pug and tries to bite him… husband took her to the vet today for a shot and the vet said that was normal behavior.. however this afternoon went too far… she bit him and made him bleed he was pacing and panting back and forth for a while so I just separated them and left them in diff rooms… I’m not sure what to do. I don’t wanna turn her back to the shelter as I feel really bad but I can’t put my pug at risk of getting hurt again… any advice would be appreciated:(