Hi Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern...
Yes, intake of a plan B pill can cause early vaginal bleeding before your expected period. The bleeding you had must be
breakthrough bleeding which normally occurs within 3 weeks of intake of plan B pill. This is normal feature of intake of a Plan B pill & you should not be much concerned about it. Breakthrough bleeding most probably means that intake of postinor 2 was successful in preventing pregnancy.
However the
abdominal rash should not be linked to plan B intake a week earlier. It could be related to
allergic reaction to medicines given for treatment of
Urinary tract infection(UTI) or may be allergy to other thing.
Don't take plan B pill too frequently. Use condom or regular
contraceptive pill regularly as method of contraception in future. Regular intake of plan B pill can cause irregular bleeding & other serious side effects.
If rash persists, you should visit a physician
Don't worry you would be fine
Hope this information helps