Traumatic ulcer or blister: This is the most likely diagnosis due to the description of the blister being painful when disturbed, suggesting a possible traumatic origin such as biting the tongue or irritation from a sharp tooth or dental appliance.

Herpes simplex virus (HSV) infection: HSV can cause painful vesicular lesions on the tongue, especially during primary infection. The presence of multiple vesicles that rupture to form ulcers would support this diagnosis.
Aphthous ulcers: Although typically found on the buccal mucosa, aphthous ulcers can occasionally appear on the tongue. They are painful and can start as small vesicles before ulcerating.
Oral lichen planus: This chronic inflammatory condition can cause vesicular lesions, but it more commonly presents with white, lacy patches or erosive lesions.

Squamous cell carcinoma: Although rare, any oral lesion that does not heal within 2 weeks should be biopsied to rule out malignancy. A vesicular appearance is less common for squamous cell carcinoma, but it cannot be ruled out without further investigation.
Erythema multiforme: This is an immune-mediated condition that can cause oral ulcers and vesicles, often accompanied by skin lesions. It can be triggered by infections (like HSV) or medications.

Pemphigus vulgaris: An autoimmune disease causing blistering of the skin and mucous membranes. Oral lesions are common and can precede skin involvement.
Bullous pemphigoid: Another autoimmune blistering disease that can affect the oral mucosa, though it is less common than pemphigus vulgaris.
Angina bullosa hemorrhagica: A condition characterized by the sudden appearance of blood-filled blisters on the oral mucosa, often on the tongue or buccal mucosa, which then rupture to leave ulcers. The exact cause is unknown.