A 30-year-old male underwent tooth extraction for dental caries. Now he presents with fever and trismus. Oropharyngeal examination is revealing that the tonsils are pushed medially. There is also a swelling in the neck at the upper border of sternocleidomastoid muscle. Most likely diagnosis is:
Retropharyngeal abscess Ludwig's angina Peritonsillar abscess Parapharyngeal abscess