Newly diagnosed small fiber neuropathy - muscle twitching and mottling

Hello, my son is a 31 year old with type 1 diabetes. His neurologist diagnosed him a few months ago with 'non-length dependent' small fiber neuropathy and told him to come back when he needed pain medication. Since then, he has been slowly experiencing burning and numbness which started in his hands and feet but is also on his face, chest, and back. Two questions:
1) He's experiencing some muscle twitching in his calves - is this typical with SFN?
2) He's having red/purple blood vessels (mottling) show up on his inner thighs and it comes and goes. When it shows up now, it goes from his inner thighs down to his ankles. A few weeks ago, there was some mottling on his back but was only there for a few days. Do others have mottling with SFN?

Thanks.