They represent hard work and effort. Often, they may indicate a loss of sensitivity. Perhaps, it is time to pay more attention to your emotional life.
[1]A callus forms when a certain action is repeated over and over, hardening the skin with small amounts of scar tissue. This allows for these motions to continue without harm or damage. Calluses are evidence of hard work and accomplishment as well as the skill to create and build. In a dream, they are asking you to consider where you have been putting your effort and attention.
[2]