Purple that will fade to purple over pink base

Most purples fade either pink or blue. It's just the nature of dyes. There's often a stronger pigment that lasts longer. Going to a hairdresser won't help.

One thing you could do is add blue (just not a green based blue) to your conditioner. Each time you wash your hair, use the blue conditioner and leave for 10 mins. Then rinse as normal. It'll give your pink hair a blue boost and help it look more purple.

Then when it comes to redo the purple, dye as usual. Then put some of the purple dye in the conditioner instead this time. Do the same as before (though you can leave it on for less time) and it'll help keep the purple fresh. If it starts fading pink still, add more blue.

Directions Neon Blue started off as a dark purple with a blue tone to it and faded to lavender on my bleached hair. You can also try to add Neon Blue to the conditioner as Janine said above.

Pravana violet is true purple that fades to lighter shades of purple. Its really strongly pigmented so little bit goes long way. On my pale yellow hair it faded do lavander then to white/silver 🙂