Your symptoms likely suggest a viral infection, such as Coxsackievirus, or aphthous ulcers triggered by a weakened immune system from your cold. For treatment, you can take over-the-counter paracetamol or ibuprofen to relieve throat pain and fever. Apply an anesthetic oral gel or use an antiseptic mouthwash to soothe the tongue blisters. At home, gargle with warm salt water daily and stay well-hydrated. Avoid spicy, hot, or acidic foods, as they will irritate the blisters. If symptoms worsen or persist beyond a week, please consult a doctor.