Without examination confirmation of a diagnosis is tough but it can be due to acne vulgaris. Acne is due to an overactivity and plugging of the oil glands. Acne usually lasts until age 20 or even 25. It is rare for acne to leave any scars unless picked.
Ask your boyfriend to just keep his face clean by washing with a mild soap atleast twice a day.Pat it dry and do not rub it.Avoid picking or pressing the acne.He can also use Benzoyl peroxide 5% lotion or gel once at bedtime. An amount of lotion the size of a pea should be enough to cover most of his face. If his skin becomes red or peels, he is using too much of the medicine or applying it too often.
If still the symptoms do not improve then pls get a clinical examination done by a dermatologist.
Hope it helps.Take care and pls do keep us posted on how your boyfriend is doing.