It looks off because you need the 'deepest' parts to be light, and what you've got is light outlines around where the yellow wash has settled. You're aiming for the opposite of what we normally want when shading.
Give it some off-white highlights in larger areas of exposed lava.
Then you went a bit too dark, too quick. Glazes red then some oranges over the rhinox hide a few times (avoid getting it in the cracks) to bring it a bit lighter near the edges, then darken in with Rhinox hide, then lighter with a grey (mix in some gunmetal if you like) toward the centres of the cool areas.
Then you can touch edges in areas near the very lighter parts of the 'lava' with some lighter edge highlights, ranging from orange to yellow but avoiding going too light. Subtlety works here.
Excuse the very old
WIP (pay attention to the lava only) but you should have something like: