I had a frozen package of bacon. I only wanted to use half the bacon, but couldn't separate the frozen bacon strips, so I defrosted the whole package in the microwave. The bacon got quite warm - not fully cooked, but smelling like bacon. I used what I needed and put the rest in the fridge immediately. I'm planning on using the rest of the bacon in a few days. Is that a good idea, or should I just throw it away?
You can use it in a few days, that will be fine. Issues with food safety come into play largely when food is kept in the danger zone, around 40-140F for an extended time.
The texture of the bacon might not be quite as good since it's kind of like the second time you'll be cooking it.
You didn't say HOW LONG it was "quite warm" nor how warm "quite" is, but assuming you mean it was a room temp for a few hours, it's fine. In a more general way, if it doesn't smell bad, it is probably OK.