It sounds like your mum has recurrent episodes of angioedema which could be an allergic reaction to various triggers (e.g. food, medications, insect bites or stings) especially if associated with an itchy rash like hives. One particular type of medication that can cause this is an ACE inhibitor (e.g. lisinopril, enalapril) which is a drug used for high blood pressure and also heart conditions. It is important to make sure the episodes of lip swelling are not associated with difficulty breathing or wheezing that may suggest a serious reaction that needs immediate medical attention. It doesn't seem like the leg cramp is related though. You can consult your family physician or an allergist.