Discharge from wound post lumpectomy

My mom had a lump removed in her breast.  The lump was located behind a cyst (which was detected and left alone in previous mammograms).  The lump was very deep in her breast.  Anyway, both were removed and she was told the lump was benign tissue (fibroid).  Since the surgery she kept telling me she felt a minor twinge of pain in the lumpectomy area and now 4 months later she developed a small pimple type thing and when she squeezed it a yellowish discharge came out (she said right in the center of the incision). She kept messing with it and a pinkish color was in the discharge.  Now, she is very worried and she does have an appointment with her doctor, but if you could give me any info. on this I would appreciate it as I would like to calm her fears before her doctor appointment (which is in 4 days).

[CCF-RN,MSN-JS]

Dear Manny, This may be similar to what happens when a pimple comes to a head, and part of the healing process that needs to happen.  She should leave it be (not squeeze) till it is checked by the doctor, they will check if there is any suspicion of infection.

[Oldgal]

I had a mastectomy on August 21, 2001.
The wound has JUST begun to close up
after draining yellowish fluid for several weeks.

My question is mostly about the "pouch"
that I have behing my underarm, which is most frustrating.  I have complained to my surgeon about this and his answer is for me to get plastic surgery to have it removed if it bothers me.  He does not know what causes this lump.  

I had 9 lymph nodes removed and the drains were left in only 3 days. I had a "drive-thru mastectomy" and had to return to his office on the 3rd day which is when he removed the drains.
Too soon??  Would this cause this pouch
to form?  Plastic surgery????