You need to rest the injury and work around it by decreasing the weight you use to the point that it is not painfull.
The truth is you cannot grow all the time. You need to cycle your training approach to take into account that these overuse injuries are going to crop up. Wait for it to heal, then hit it hard again, and I promise you, you will quickly break past your last plateau.
If you don’t do this, you will gradually acrue more scar tissue, and overtime you will lose strength in the arm, causing your other arm to carry more of the load, which can lead to a whole set of other issues. (I am sure BBB can expand on this.
If your body is injured, it will direct more of its energy towards healing the injury instead of building muscle. Keep reinjuring and you will be retarding your gains.
Not only that, but injuries stimulate production of cortisol which is a hormone you want to minimize.