You didn't mention exactly what you noted, but if your incision has opened up and blood drained from it, you should see your surgeon immediately. Any tiny opening could be as simple as a dissolving stitch giving way and allowing a bit of drainage, but any spot that lets blood or fluid OUT can also allow bacteria IN. If the incision communicates with the implant pocket, contamination or infection around the implant(s) cannot be eliminated by antibiotics, and the implants must be removed to cure the infection.
So, as you can see, even a tiny open spot in a breast implant patient's incision CAN be a big deal. Or maybe nothing!
If you are simply noting bruising without any drainage or opening in your incisions, this is indeed normal in a few patients at this point in your recovery.
Bottom line here: you should be seeing or at least talking with your surgeon about exactly what you are experiencing. If it's nothing, you want to find that out and be relieved of this worry; if it's the beginning of something worrisome, you (and your surgeon) want to "nip it in the bud!" Call today for an appointment ASAP!