Hyaluronate-based soft tissue fillers are safe for patients with autoimmune conditions, like C.R.E.S.T.. I tell physicians to be aware of increased fibrosis and the obliteration of planes (as part of the pathology of scleroderma spectrum disorders), but aside of this, I believe that patients get good results when their lips and perioral (= around the mouth) areas are treated. In fact, it may even be a nice idea to use some botulinum toxin periorally, to assist with the concentric furrowing. The advice given to avoid fillers in patients with C.R.E.S.T. was more relevant when collagen was injected, i.e. 20 or so, years ago. Hyaluronic acid fillers are not of animal origin and have very low immunogenicity Of course, you must understand the potential for 'routine' adverse events and complications, inc. 'delayed hypersensitivity reactions' - ask your physician to discuss these considerations with you. The key thing I'd counsel you against is undertaking deep skin-resurfacing.