Can I get a disease if a lizard bites me?

That may be a cabbage maggot, also called a root maggot. Most other pests stick to eating the leaves and stems of radishes rather than going after the root.

No, people typically don't even notice when they're bitten. Roughly 30% of people aren't even reactive to bed bug bites and they won't have any sign that they've been bitten.

No.

The lizard is venomous, and bites Mr. Spock.

The effects of the bite are usually pretty limited and should go away within a handful of hours.

You can apply a calming lotion or some chamomile oil. Some people prefer to take antihistamines to alleviate the symptoms until the itching subsides on its own.

You need to be patient. Let your animal get comfortable feeding without you watching. It also may be nocturnal and not want to eat during the times you are trying...

Iguanas, bearded dragons, uromastyx lizards and some skinks are omnivorous, hence they'll be able to feed on either. Other lizards are strict carnivores, mostly feeding on small invertebrates.