--I would doubt that a dumbell exercise or massage would "cause" a small fiber neuropathy--the small unmyelinated fibers are embedded in the skin and it would be very hard to damage them that way.

It would be much more likely to damage larger, myelinated nerves through bad exercise technique or bad massage technique by causing these to be misplaced in their tracts and or to swell. Of course, this might still be painful.

Also, can you distinguish between "regular" nociceptive pain and neuropathic pain? Neuropathic pain is generally not like regular pain; it has a burning, dysethetic quality to it--like a bad sunburn someone rubbed with sandpaper--that is quite different from the general "bruising" pain, as neuropathic pain is caused by malfunctioning nerves, rather than inflammatory excitiation of nerves from other causes.