Are the following sentences punctuated correctly?

Well, I never saw him!

The patient has, in the past had a problem with alcohol.

As there is no contraindication, a biopsy was scheduled.

2 answers

The first and third are correct.

Re-think the second. See #4 in the link I sent before.
The nursery rhyme begins this way: “Mary had a little lamb. . . . And everywhere that Mary went, the lamb was sure to go.”