Does Venus Opposite Ascendant makes someone ugly?

Yes, you're right, having Venus close to the ascendant would probably give the person good looks, (there may be other things in the chart to counter this though, like Mars close to the Sun etc), but being opposite is actually close to the descendant. This doesn't give bad looks but what it does show is that relationships are very important to the person and these have to be harmonious, otherwise the person would be extremely unhappy.