tone up for the upper arms

Hi I'm a little worried to put it mildly of when I do lose the weight I want to lose it's going to leave me with dreadful upper arms like excess skin type thing and I was just wondering how I can prevent as much of that as possible.

I just feel like I will lose the weight and then look even more horrible than now with rubbish arms and I feel like I'm going to end up wrapping myself up all year long.

Please help!!!