It depends on how severe the light leak is. If an area is completely blown to pure white, there usually isn’t image detail left to recover, so your best option is retouching with cloning/healing if the damaged area is small.

For partially overexposed areas, you may be able to improve the scan:

• Try rescanning the negative multiple times at different exposures (normal, lighter, darker).
• In Photoshop, combine those scans with masks so you can use the version that holds the most detail in each area.
• Use Shadow/Highlight adjustments to pull back highlight detail where possible and open darker areas if needed.
• Local dodging and burning can help smooth transitions and make the repair less obvious.
• Auto Tone/Auto Color may help slightly in some cases, but they won’t restore lost detail.

Unsharp Mask can improve perceived detail or edge contrast, but it won’t truly recover detail that was erased by overexposure.

So: partially fogged/light-leaked areas may be salvageable with careful scanning and masking; fully white areas generally are not.