Go to the laundry and try to shape the sweater. Generally speaking, there is no problem. You can also steam it with a steam iron and then make the deformed part of the sweater tighter. Be careful not to burn your hands. See if it can be restored.

Also, if it is pure wool, it can be washed with shampoo, and the reverse side can be washed gently by hand, which can minimize the pilling. It's best to find a professional laundry when drying. If the sweater is more expensive, hehe.

If you already have a hairball, trim it with a hairball trimmer. You can buy one with the trimmer in 20 yuan.