Hi gnu, Hang in there! I have gesso’d over area’s and repainted them. You don’t want to go heavy with the gesso–just enough to ghost-out the problem, or you’ll have a surface texture inconsistancy with the rest of the canvas/painting. I gesso over just enough of the color to not distract me during the correction.
It may not be as bad as you think–can you post a pic? (you don’t have to, but sometimes a small mistake looks HUGE if we over-focus on it).
I have one on my easel right now that may get a gesso correction. I’m working around the area and will see how it looks when finsihed.
Sometimes the mistake is not a “paint mistake”, but a “glitch in expectation”.

I try to get my whole sky/background complete first if it’s a big expanse and not touch it again..the very first lessons I discovered for myself when first starting out in acrylics..(gnu)

Oh this is good advice – as I know to my cost!!!!!

Follow gnu’s advice from the rest of her post too and you may be able to rescue it.
My own recent attempt to paint over a bk/gd again and again because I hadn’t got it right first time led to me cutting and peeling………don’t ask!!!!!!!!

My lesson? Think about the bk/gd much more carefully in the beginning!!!!!

The painting I’m working on now (for Fall Up Top project) has had the bacground changed 2 times, and the foreground once (getting ready to do that again!). I don’t paint thick, so I just paint over what I don’t like. If I have to do it a bunch of times , it won’t matter.

Without seeing your work it’s a little hard to give specifics.
When appraoching skies or water I always adopt a layering approach – applying a thin wash of appropriate colour, let it dry, do another and so on. This gradually builds up colour and adds depth and often interesting variations in value. It is also good for blending wet in wet for sky gradations.
For your problem, I would suggest going over the sky with your predominant sky colour, adding progressive layers and observing the effects with each layer. You might be pleasantly surprised at the depth you will generate.

Lol! You’ve got the right attitude now anyhow – so you’re halfway there.
Good luck and keep us posted.

Christine

Painting is about altering until it is the way you want it, there is no such thing as mucking up. When you started you covered up the base coat and so on. I continuously add or subtract paint until I have what I am happy with, it’s never a muck up so to speak. A muck up is when the dog jumps on it with wet feet…..that’s a muck up.

It’s acrylic, just paint over it, either with a dry brush a little at a time for lots of control, or swathe the whole thing in new wet paint….its up to you, either method will take you back to the alteration process. Good luck.