Hello and welcome to just answer. Our mouth is a mirror of health or disease, sentinel or early warning symptom. We come across many patients in day to day life and I can tell you that tissue lumps/ growths in ones mouth come in all shapes and sizes. Although most of them are not a cause for any worry, the fact is that any abnormal growth should not be there in ones mouth. There can be a list of possibilities contributing to this condition & this is not something that I or anyone else can diagnose it over the internet. More precise details the size of the lump (as you told me), its color relative to the rest of the cheek, and their surface texture would be helpful but not necessarily diagnostic. Ultimately, a clinical evaluation by a dentist or a biopsy will likely be required to let you know exactly what this lump represent and, if necessary, how to treat them. However, the nearest possible condition pertaining to the above symptoms can be a possibility of a blood blister which is caused by trauma as you might have accidently bite your cheek area. The scientific name of which is Angina bullosa haemorrhagica. See the link: http://www.emedicine.com/derm/TOPIC670.HTM
It is a condition where tense, blood-filled blister or blisters develop in the mouth which might or might be painful. There is usually no treatment required and the condition is benign and treatment is symptomatic. You can start using any otc available mouthwash which will prevent any infection and aid in healing process. Keep that area as clean as possible.
I would also recommend that you should go to an Oral Surgeon and have this looked at. This will provide a better insight to your situation. He may decide to take a tissue sample of this lump and send it to the oral pathologist for a biopsy to confirm the findings.
I hope this helps!
Feel free to contact me again if you have any doubts and we can discuss it again.
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