A one-sided swollen tonsil with recurrent tongue and throat ulcers for five months are typically not indicative of cancer, although they do require careful examination. Chronic infections, recurrent throat irritation, acid reflux, vitamin deficiencies, smoking/tobacco irritation, and persistent tonsil inflammation are common reasons. However, if a persistent one-sided tonsil enlargement is increasing, firm, uncomfortable, accompanied by weight loss, trouble swallowing, ear ache on one side, or bleeding, it should be closely examined by an ENT specialist to rule out dangerous illnesses, including uncommon malignancies. A comprehensive ENT examination and potential investigations such as a throat/tonsil examination, blood tests, and, if necessary, imaging or biopsy are the appropriate next steps. Early assessment is crucial for safety and clarity, so don't panic but also don't disregard it.