Highlights are the bane of my painting existence as well, and I as well am very hesitant in using bright ones. I fear I might muck up and have to start over.
Best advice: get over yourself. It is hard, I know. But mucking up is part of the learning curve. Don't fear it, embrace it. You'll notice it comes out much better in the end. Especially the first layer after the basecoat makes me wet myself, each time. "Noooo, it looks so bad!" But go on, put on the second layer and perhaps third, and it'll look great. Try your hand at some feathering even, have a moist second brush at hand, and when you get the feeling the contrast between basecoat and highlight is too great, feather it down at the edges.
I am very much a beginner as well, but I find just trying various techniques without fearing failure, helps you improve greatly.
As for your figure, maybe highlight her skincolour a bit brighter?