a snake according to the bible[Gen 3:1-5] represents deception,remember the Eve incidence in the garden of Eden,the devil came through a snake.
The right hand represents diligence or productivity (fruitfulness)[Gen 48:13-20].
Now coming to your dream, I think it may mean you are being targeted by the enemy in the area of your work. The best thing to do is to pray about it with knowledge that Christ has already conquered all these forces of darkness. You are in Christ seated in the Heavenly places far above ALL principality,power,might and dominion.
Your dream is a revelation it has been brought to light,so it has no power as long as you take the right steps.