Plz dun worry ...or jump to conclusions...get it evaluated dy a dentist nearby...

Please give some details about colour,size,shape, location,ur habits,or send me a good quality picture.

I second the opinion of Dr Kshitij Rohilla . Just a point to add on to it would be that if it's recurring at the same place every time then there may be chances of having a fractured tooth or broken or dislodged filling due to which u may have developed some sharp edge that might be constantly irritating the tissues adjacent to it .

We cannot give a rational suggestion without a look at the clinical picture of the affected area. Please post one if possible. A normal oral ulcer usually heals within 7 to 10 days. But such a long duration is definitely something that should not be ignored. But we should not rush to diagnosis like oral cancer without a proper clinical checkup and a detailed clinical history. Even if there is a clinical doubt a biopsy will be required to confirm the diagnosis. Regards.