You can look at this tender lump as a good thing, even though it does not seem like it at the moment, because it is definitive proof that the radiofrequency is killing your fat cells at a very rapid pace. The lump is a basically a ball of inflamed dead fat cells. Your body has not yet cleared these cells. It will eventually do so. In my office, we use Cellutone after each treatment to help break up the fat cells and clear them toward your lymphatic drainage system. Making sure you are extremely well hydrated by drinking at least 64 oz of water daily the week before treatment can help to prevent them. In addition, always communicate with your provider if you have hot spots during treatment so that it can be addressed instead of "sticking it out", so that they can help prevent fat necrosis lumps. You should delay your next treatment until this tender lump improves or it will continue to worsen with more dead fat cells around it. Cellutone treatments can help it to resolve more quickly as well.