. . .technically speaking, small fiber neuropathy--the dysfunction of thinly myelinated and unmyelinated sensory nerves that subsume the sensations of pain and temperature, and many autonomic functions--cannot result in muscle weakness, as those types of fibers don't ennervate muscles.

That said, though, many report increased fatigue from the condition, not only from autonomic disruption but just from the day to day grind of dealing with symptoms, which is often interpreted as increased weakness. And, of course, there is nothing that says one has to have an isolated small-fiber involvement--while some do have their neuropathy limited to that type of fiber, many have damage to both small and larger fibers; the latter control the sensory impressions of balance in space, vibration and mechanical touch, as well as voluntary muscle control. Generally, those who have noticeable weakness in muscles from a neuropathic process can have that picked up by a well-done EMG (unless the weakness is very recent--that type of damage often takes some weeks or months to make itself manifest on testing).

I'm not sure about hives being caused by small fiber neuropathy, or even large fiber, but there are a lot of conditions associated with small-fiber neuropathies that may produce skin abnormalities that look like hives, from the rash of dermatitis hepatiformis in those with celiac/gluten sensitivity (which can cause neuropathy) to the rash disruption in a number of vascular and connective tissue autoimmune conditions (from lupus to Bechet's to Churg Strauss to polyarteritis nodosa).