Hey Liz
From your message you indicate a difference in physical appearance from the right side when compared to the left. However, is there a
strength difference?
If you are training both sides with the same exercises and use the non dominate side ocassionaly the day when carrying things, bending, etc. then I wouldn't worry too much about the differences right now.
What you may be seeing is asymmetry caused by muscle that is still concealed under fat tissue. The thing to keep in mind is that there may not be a logical pattern (at least to us) in how the body taps into our fat reserves for energy. As we get closer to our goal (and I notice that you are about half way to yours) we do begin to see the areas that are more resistant to fat loss begin to lean out more.
Now, if you notice a significant strength difference between the right and left side, that's something we can work on. Would be helpful to know what you are doing for your strength training.
There are different ways to train based upon your goals. I'm thinking your goals are probably more about hypertrophy in nature. (Like to see some lean mirror muscle when you flex that bicep in a tank top right?) Stay within a rep range of 8-12 reps. That is, choose a weight that begins to fatigue your muscle by about the 7th to 8th rep but you can still complete till about the 10th rep. Its the last two reps of the set (they gotta feel HEAVY) that really matter. If you can do more than 12, go up in weight. Don't waste your time.
By the way, body weight exercises are highly effective for building beautiful arms. Biceps and triceps get a great workout while doing pushups and all the amazing variations beyond the plank: Incline, decline, pushups with a ball under your feet, pushups with med balls under your palms, pushups with dumb bells, t-pushups, t-pushups with rows...
Hope this helps.