Hello,
It is possible that this was a regular break out of acne as doxycycline is the treatment for acne also and it is less likely for doxycycline to cause such a rash. In case of an allergic reaction
clean by washing with a mild soap atleast twice a day. Pat it dry and do not rub it. Avoid picking or pressing the bumps. You 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 your face