If i had toothache, fever, headache and numbness around the lips, what might had cause it?

Toothache: A severe dental abscess can put pressure on the nerve usually on the lower lip and cause a certain degree of numbness. With the level of symptoms you are describing you should seek out care asap.

The tooth infection: The infection of the tooth can cause all those symptoms, the infection can put pressure on the nerve that goes to the lip and cause the numbness.

Infection: Based on the limited information, this is most likely an infected lower premolar tooth. If there is an abscess, it can put pressure on the nerve that supplies the lower lip on the affected side. If it is all the lips, it could be a viral outbreak or something else. Either way, it would be wise to see an endodontist or skilled dentist.