labels are not registered in the blockchain, it is an internal label that affects only your wallet software. Probably if you reinstall your electrum, or recover it in another computer, the label will be lost, but funds will not be affected.
If you recover your wallet from seed, labels will be lost. As bitmover said, that doesn't affect your funds and you will be able to see all your transactions.
note: You can activate the
Electrum label sync plugin to save your labels on Electrum servers and recover them later (
make sure to read the part about privacy implications).
You can also export labels and save them in a JSON file that can be imported later.