I returned from a camping trip two days ago and have a red & slightly raised bump on my right breast that is sensitive to touch and now is bruised a bit. i'm wondering if it's a sspider bite or more?

Does sound like bite: Without a photo, it's hard to diagnose which type of insect it might be. Given that you were camping, of course it could be spider, tick, flea or others. If looks like a bullseye, then you want to see a doctor, could be a tick bite. Of course, wouldn't want to miss something more ominous like inflammatory breast cancer, so keep a close eye on it and go to doctor asap if doesn't get better.

Warm compress: See if a warm compress and antibiotic cream will help. A bite or superficial breast infection is possible, if worsens, see a breast or general surgeon for care.