That’s great news! Why not get paid more for doing something similar? You’re so lucky that Company B got back to you in time before you started working for Company A. I suggest you go for it as you don’t want to regret it later on that you missed your chance for a better offer.

As a head hunter I can’t even begin to tell you how frustrating it is when candidates suddenly change their mind, or worse, fail to show up.

Of course, you have every right to call A and tell them you've had a chang of heart. They would probably appreciate your having the decency to inform them.

I just can’t help but wonder how do you define the term "better" with regards to the other offer. Is it only a salary issue? Otherwise how could you possibly "rate" which of the two is better without trying first?

I can't tell you which job to take, but I want you to realise that you are responsible for every decision you make.

Frankly, I don't know how you came across a second offer at this stage in the first place, since after accepting a job, you should have stopped looking.

This is a valuable experience for you to learn from, so as to avoid making a similar mistakes in the future.

Whether you pick A or B is entirely up to you. Just make you don’t change your mind again.

Also, remember not to only focus on the money. Focus on the job itself.

Another thing: Don't make up stories for turning down A. At the same time, don't disclose B's offer. Simply apologise for all the inconvenience you must have brought them, and say that you're deeply sorry. That’s it. If you give A the feeling that you're trying to bargain for a better offer, you're essentially destroying your career.

Next time, consider all opportunities and possibilities before you making up your mind.