I think the 'temper' of the coil is knackered by the heating.
It would be in bad temper if you re-heated it and pulled it out, and might collapse again or break. Never mind the wonky shape, as it would be hard to get the perfect regular spiral it had when it was wound.
It also sounds 'cruel and unusual' and not the sort of thing a civilised man should do to a spring, just IMHO.
Maccari in the US likes to use shorter, stiffer springs and then space them to get the right power. No cutting or heating or crushing involved.
Good luck!