First of all, let me reassure you that it is not cancer.
This is going on for a year, and you have tried cortisone
too for this. Now, you also see them as spots, with pus or fluid.
I should say you this, the general condition of any person is known by looking at their lips and nails.
The symptoms on your lips may be a sign of underlying systemic infection.
You need to consult a general physician, get routine blood investigations done and find out the exact cause of the same. It is termed Angular cheilitis
Please do not be afraid, meet a general physician soon and get it resolved.
Hope this helps.