Help! What should I do to cover up this naked space on my arm ?

This is impossible to answer.  Talk with a professional artist, or at least show us your entire arm.  You could put two frogs there, or a bunch of bees.  You could put a stack of books.  You could put some neat plants.  You could put anything there, but we have no idea if its a good suggestion because we don't know what you have going on with the rest of your arm or how big a space you have to tattoo.  

Honestly, I would ask a tattoo artist if they could design a piece specifically for that space. If you're open to different ideas it would give them more freedom to design something that could fit perfectly. 

How about a tattoo that says” I admit I am a loser!”

a chain of thorns around the rose? 

Masking tape.

How about dollar signs with wings?

Put an awesome collage of flowers and p*nises, see if anyone notices...