I'm actually a lot more worried about the bottom panel being bowed out and not fitting cleanly. Looks like something got just crammed into the case when it was put back together and it didn't quite fit.
That looks like the battery is expanding. That's a sign of a failing battery. I'd get it replaced ASAP or it may damage other components of the laptop leading to more expensive repairs.
That looks like the battery is expanding. That's a sign of a failing battery. I'd get it replaced ASAP or it may damage other components of the laptop leading to more expensive repairs.
The battery is at the front of the computer, under the trackpad. That picture is the back, near the hinge. This isn't a battery bulge as it wouldn't bulge in that location.
This looks like the person doing the repair wasn't horribly careful with reconnecting cables, one is now frayed and connected improperly and is causing the bulge.