Answer
Go back to the grit that still cuts the rough spots, level them, blend the area, then step finer again.
Why it happens
The rough areas were not leveled at the earlier grit before moving finer.
Recommended grit
Return to the last grit that still cuts the rough spots, then step finer again.
Wet or dry
Dry for wood and general prep; wet for fine finishing stages.
Success check
The whole surface feels even before the final grit.
What to do
- Mark the rough spots.
- Return one or two grits coarser on those areas only.
- Blend the repair area with the surrounding surface.
- Continue through the normal grit sequence.
Avoid: Do not keep polishing rough spots with very fine grit.