You may have hurt your back. When skipping rope, you should choose a soft ground, or put a yoga mat on it, which will help your body cushion. If these are not complete, then when skipping rope, don't stretch your legs too straight, bend slightly, and keep your body forward to a certain extent, which can also play a good buffering role. The function of cushioning is to help reduce the injuries caused by skipping vibration to ankles, knees, hips, waist and head and neck.

You stop training now, do some massage and see how your recovery is. Another thing, if you are just starting to exercise, I suggest not skipping rope 1000 times. This load is actually quite heavy, which is easy to cause muscle damage.