What are 'packets' in hair colouring?

[Horsemad]

I'm having my hair coloured at the w/e and the hairdresser mentioned having 'packets' done. Is that highlights and if so, what would happen if I chose to colour my hair myself a month or two later?

Would a home colour work ok on top of highlights?

Yes - 'packets' are the foils used when your hair is highlighted.

Colouring your own hair after highlights might not work very well - check colouring packaging - many say 'not suitable for previously coloured or highlighted hair'. I don't really have any experience myself though - maybe someone else will be able to advise (i.e. it may work but the hair colouring manufacturers just covering themselves...?)

Hmm, thanks. Not sure I want highlights then! Had them a year ago and they've grown out now so will just get the grey roots touched up I think!