Several conditions can cause your hands to be numb. The spinal nerves originate in your neck and provide sensation along your arms, to the tips of your fingers. Carpal tunnel syndrome is a condition caused by compression of the median nerve in the base of your palm, just above your wrist. Although this is a common disorder, other disorders can also cause numbness in your hands.
Eris is a dwarf planet and a trans-Neptunian object (TNO). It is in the outer Solar System. It is the largest dwarf planet known, even bigger than Pluto, at 2400 km in diameter.
If you mean the dwarf planet 136199 Eris then I can answer to the question. Eris has a rocky core and icy mantle like other large trans-Neptunian objects like 20000 Varuna, 28978 Ixion, 38628 Huya, 50000 Quaoar, 90377 Sedna, 90482 Orcus, 134340 Pluto, 136108 Haumea, 136472 Makemake and 225088 (2007 OR10) for example.