Ok so I got my greying hair coloured..

[MedusaIsHavingaBadHairday]

And now I slightly regret it.
It's ok, but it's a bit too red, especially at the roots. Will it tone down over time or can I put a temporary brown (like a 8 washes type) over to tone it down a bit?

Red hair fades faster than any other colour (except the really out there ones like blue and green). I dye my naturally brunette hair a medium red (not Pillar box but not a dark deep shade) every 4 weeks and I have to use hair masks and colour depositing conditioners in between dyes to keep the colour because after two weeks it's faded a LOT. The longer I've been dying it the stronger the colour is though, so I'd say with it being red and a new colour it will most likely fade quite quickly. Obv the more you wash it the more it'll tone down anyway so you might find even after the first wash it'll fade a bit. The hotter the water should also fade it quite quickly.

I think a brown shade over the top would probably kill most of the red altogether?