You could try adding yellow only to the joints and forks, the area where it would be the hottest.
Also you probably should have done a darker red for the base, then slowly blended colors up to the forks and joints. It seems like you may have started it as too light of a red shade.
This is how I did my lava base for my Vulkan. It's red gore-blood red-to orange-yellow-white with 50/50 gradients of each color leading to the next.