On my lower and inner lip mucosa, there is a fluid fill like vesicle for 2weeks. It doesnt hurt. Swells after meals a little more. Can it be a malignity?

No. May be a blocked salivary duct, or a mucocoele. See a local oral surgeon for a definitive diagnosis.
Harmless mucocele. Usually they're not a problem and will go away on their own. If concerned see your dentist for evaluation and surgical removal.