"after " or " later"

[YOSHITAKEHORI]

I am a little bit confused at "after" or " later", "earlier" or "before"
What is the main difference between the following sentences.
Case <1>
(a) He came back a few weeks later.
(b) He came back after a few weeks.
Case <2>
(a)He was talking with the people that he had not even been able to look at
a few weeks earlier.
(b) He was talking with the people that he had not even been able to look at
a few weeks before.
Thank you in advance.

[Mister Micawber]

.
No difference that I can see, Yoshi-- just two different ways to say the same thing.
.

[YOSHITAKEHORI]

Mister Micawber,
Thank you for helping me.

[Dippit]

Hi Yoshitakehori,
In case 1, 'a' could suggest that he he came back after a few weeks AND that he came back a few weeks later than expected.
'b' suggests that he came after a few weeks because he was unhappy - maybe his stay was meant to be for several months. He had the option to stay for longer.
In case 2, I agree with Mister Micawber.

Hope this helps,
Dippit