This case highlights the role of stress as trigger factor of HSV-1 reactivation causing recurrent intraoral herpes mimicking herpes-associated erythema multiforme (HAEM). A 24-year-old female came with chief complaints of pain in the oral cavity followed by painful swallowing and fever. She admitted under stress due to family problems and also had insomnia for the last three years. Extra-oral examination revealed serosanguineous crusts on lips that were painful and easily bleed. Intra-oral examination showed the white-yellowish multiple and coalescent ulcers, irregular, and painful on the left and right buccal mucosa, upper and lower labial mucosa, dorsum of the tongue, the floor of the mouth, and oropharynx. The results of the Depression Anxiety and Stress Scale (DASS)-21 examination were moderate depression, extremely severe anxiety, and moderate stress. The results of the HSV-1 IgG examination before and after therapy were positive with titer > 200 U/mL. Pharmacological therapy included acyclovir 200 mg tablets, multivitamin, benzydamine HCl lozenges, 0.025% hyaluronic acid mouthwash, 0.9% NaCl, and 100% petroleum jelly. Non-pharmacological therapy included stress management such as self-encouragement and referral to consult with a professional. This therapy generated significant result. In conclusion, stress affects many systems in the body, including the oral cavity. Stress is one of the trigger factors for HSV-1 reactivation which can cause oral manifestation. Early detection of trigger factors is important for better treatment result.