Rather than blindly going for the medications, i suggest you to visit the dentist
ASAP and fist get the root cause know as there are many factors leading to gums swelling and tender. Few to be cited are:
improper brushing technique
calculus and plaque
or it can be improper brushing technique etc.
So, start brushing twice daily with proper brushing technique, do flossing daily and use mouthwash gargles and don't forget to visit the dentist...