Which colour will go over stained turquoise

You've a few options really.

Pink, which will go purple. If it's very faded and you're happy with a deep pink you might just get a good pink.

Purple which will be a more blue toned purple. Add more pink for proper purple.

Green, which will pull more a bit more blue. Add a little yellow to make it more proper green.

Add Fluorescent Glow for a really vibrant bright green or super vibrant turquoise. Obviously other yellows will work, but some are a little too orange toned, so avoid any of those. Make sure it's on the green side.

Red might cover it completely. Go for an orange red and it should help tone the blue.

Really, the only thing that won't work at all is orange and yellow won't show as yellow but as I said above, can be used to make other various shades of green 🙂 DO make sure you do a strand test first though, just to make sure!

That's really helpful, thank you!
I will have a think on what colour will suit my skin tone.

With neon colours, what colours happily bleed into one another?
So say top half of my hair is neon green and the bottom is neon blue? Will that bleed together okay and look okay?

Sorry it took so long to reply!

With Turquoise underneath, you'd be better off going green, to blue, to purple. That's the mix I've had to do for a long time due to turquoise staining.

The only colour you're guaranteed to go between blue and green is yellow and that's not going to happen over turquoise! It'll just be another green. I've managed a yellow, to green, to pink and the fade was pretty iffy between the green and pink.

Hopefully attached is a photo of the yellow, green, pink! You can see I stayed away from neon in the green but went super neon in the pink and yellow as it was the only way I'd be able to get a good blend from green to pink.

(edited to add, lol forgot it's currently my profile pic! It was almost a year ago, so I'd forgotten I hadn't changed it here)