Please recommend the best beer to prevent hangover?

There isn't any: I think you have this backwards - IT IS THE BEER YOU NEED TO AVOID TO PREVENT HANGOVERS. All forms of alcohol can cause hangover, but they are more common in darker forms of alcoholic beverages = whisky, red wines, beers. The way to prevent hangover is not to drink to excess. If you have frequent hangovers yet continue to drink heavily, you have an alcohol problem. Talk to a counselor or doctor

Alcohol Poisoning: A hangover is a symptom of alcohol poisoning. Only an alcoholic would ask this question that you have bravely presented to us today. I do not make this statement as a judgement. But, it is a frank assessment that it very well may be time to speak to your doctor about your drinking.