Hi! I Have An Allergy On My Face (we Are

hi! I have an allergy on my face (we are making a test and we think it was an allergy for doxycicline) and my doctor prescribe me to apply in the morning effort cream during 6 days + during next 6 days every second day (it means 3 more times). Is the treatment not too long because I am afraid of side effects? Can I use the cream in the evening, but not in the morning? will it influence the efficiency? Should I protect myself from the sun since we are planing to go to the beach? thank you!