Using spray on hair dye for dreads? +wigs...

Hey everyone! A complete newbie here, this is my first post

I have been dreading my hair for 8 or 9 months now and it is pretty wild, there are some cool locks forming and I love it so far. My problem is that I'm going to go to a con this summer and I'm planning to cosplay a couple of different characters. The other one has quite messy hair so it'd be great if I could just dye my hair black for that day somehow, since wigs are a bit problematic. 

So, is spray on hair dye bad for dreads? I could do a deep cleanse afterwards.

Also, any tips on wearing wigs with dreadlocks?

i have zero experience with that but as long as its sprayed on the surface and rinses out with ease ..it maybe ok but..since i don't know for sure use at your own risk

but cosplays not so much about realism i mean if a black man can play a white character or a Chinese woman a black male character or a white chick play a dog...why cant a redhead play a black haired character

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My new book Ban The Taboo Vol 1

Thanks for answering! I'll try it  

And yeah, that's true, I just like to get as near to the original character as possible appearance-wise. It's just a lot of fun in my opinion