I have new bumps 3 days after applying permetherin. Has scabies returned?

Hard to say. The bumps appear as a skin reaction to the debris left in the tunnels the scabies leave under your skin.That reaction does not stop at the point of treatment, since it may take a couple of days to show up.It is a little early to worry about treatment failure. Give it another week, and your sites ought to be healing. Re-infection is a possibility if bed linen and clothes have not been cleared.