谁能帮我看一下这个句子哪里语法不规范吗?顺便帮改下

题目

谁能帮我看一下这个句子哪里语法不规范吗?顺便帮改下
What's more terrible is that the patients who give themselves treatment by using the computers instead of seeing a doctor sometimes might be misdiagnosed and their illness will be more serious,which will lead to the serious consequence.

答案

What is worse,the patients,who seek for treatment by using computers instead of by seeing a doctor,sometime may be misdiagnosed ,which will lead their illness to be more serious.