Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern.. As per your complain cetrizine is an anti-allergic and is used to treat allergies while doxycycline is an antibiotic and is commonly given in treatment of pimples caused by bacterial infection.. Cetrizine is not commonly given until allergic reaction is suspected.. For pimples you can continue taking doxycycline and along with it you can take topical anti-acne treatment like washing your face with with Salicylic acid containing facewash, apply benzoly peroxide and clindamycin gel over face, apply adapelene gel at night, do cool compresses and avoid oily food.. Exfoliate your skin twice a week using a gentle scrub.. You can also go for treatments like Microdermabrasion and glycolic acid peels.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.