I am a 25-year-old male who suffers from shyness due to facial redness, which appears to be getting worse. I also have visible thread veins on my nose and cheeks. Is there any treatment?

See your doctor, who can organise laser therapy for your thread veins. However, you may not need it. You are much more aware of your facial redness than other people are, and you may be hypersensitive to it. Your doctor will also advise on how to overcome your perceived appearance - and particularly your shyness. Most people don't look at facial colour: it is your general demeanour that comes through. A smile, bright eyes and an intelligent interest in the other person will more than counterbalance what you perceive as your problem. All you need is the confidence to face the world. Your medical team will help build that up: then your redness may well die away.

Is it true that if you have a 'fighting spirit' when you find out you have cancer, you do better than if you feel depressed or are in denial about it?

No, it's not. Encouraging people to show such a spirit when they don't feel like it can be cruel, because it is natural to feel low after being told you have a life-threatening disease. A 2002 study concluded that your psychological make-up, or the way you react to the news that you have cancer, makes no difference to how long you survive or whether a cancer may recur or spread. Modern cancer management takes into account how people feel about themselves and is sympathetic to their emotional reactions. We try to lift depression and ease anxieties, but we don't force people to have an artificially aggressive attitude to their tumour.

Five years ago I had a mechanical heart valve fitted. Recently my dentist has questioned the practice of taking a large dose of antibiotics when I have minor treatment where bleeding is likely, especially when I see the hygienist. I take Warfarin, so this happens easily. Is he right?

In July Nice reviewed its advice on antibiotics during dental treatment for people with artificial heart valves. It concluded that antibiotic cover isn't needed, except if the person has already had a serious infection in the heart. So your dentist is correct. You can have your dental hygiene procedures with no worries and no antibiotics.

• Do you have a question for Dr Smith? Email doctordoctor@theguardian.com