I'm afraid of looking too different from my passport or visa?
In theory it is ok. Most passports are biometric these days and I am sure you are not the first person to not look like their passport photo. There are over 200 countries and thousands if not millions of immigration officials or border guards so other people may have had issues and can contribute here but I have never heard of there being a problem. As an aside I have heard it said that if you look your passport photo you need a holiday. So it is well known that people may not look like their passport photo which is just a snapshot of how a person looked when they applied for a passport and could be anything up to 10 years old.