The Adolfsson syndrome

I don't know if this is a common problem amongst illustrator but since I've started drawing every day I've got me a lump on my index finger, exactly where the pen is. This might be part of an evolution process or a new kind of sickness. I know that syndrome sounds a little grandiose but lump doesn't have the same ring to it, I'm aiming for posterity here . Don't want to go down in history as the Adolfsson lump. It would be interesting to know if someone else has noticed this or some other malady due to their artistic craft.