what Exactly is happening with a loose neutral? Is it most likely in the panal or in any receptical or junction box?
It can be anywhere from the utility side to the branch circuit in your house.
Look in your panel. If you see any red
wires, you have multi wire branch circuits. In one cable you have two hot
wires (power out) "sharing" one neutral
wire (power back).
The two hot wires are on different 120 volt legs. If the neutral gets interrupted between the source and where it splits
to the two different circuits, you can end up with up to 240 volts on your 120 volt circuit.
If there are no multi wire branch circuits in your house (no red wires in the panel), the problem is at your service or the on the power companys end.
Lights getting bright = bad. It will get worse until something blows up
(flatscreen TV, appliances or computers come to mind)