Thyroid UK

OT: feeling a phantom drop of water on leg, arm

I've had a recurring feeling of a drop of cold water on my bare right shin, exactly like if you were wearing shorts and dripped a single drop of cold water on your shin. Often it will happen somewhere (on the street or in the kitchen) where I might have trod in a puddle or dripped water on myself, so I look down to find my leg thoroughly covered in my dry trouser leg and/or sock and no water to be found. It happens a few times then goes away for a while.

Today the same thing happened on my right arm, below the elbow, as I'm sitting on the sofa typing.

Is this a thing? Anyone else have it? Benign neuro phantom or important symptom I should bring to the gp?

I googled it and it could be an early symptom of peripheral neuropathy - ? I also have had numbness in toes and the ball of my foot gets sore, which I think are from b12 deficiency/malabsorption (for which I've been self-injecting for about a year, loading dose + monthly injections).