Sciatica is usually not a symptom of a serious problem. In most cases, it will go away by itself within a couple months. In some cases, however, complications like permanent nerve damage can occur. Signs that your sciatica is serious and requires medical attentions include a sudden development of intense pain in one of your legs or lower back and weakness or numbness in one of your legs. Another sign of a serious problem is losing control of bladder or bowel function. Call your doctor if you have urination problems, pain that is worse when you lie down or that wakes you up; redness or swelling on the spine; unexplained fever; unexplained weight loss; or back pain lasting longer than four weeks.