Stopped shedding after PRP but my bald spots are getting bigger. Is that normal? (Photo)

Based on the pictures, you may also be experiencing alopecia areta in addition to adrogenetic alopecia.  Studies have shown that PRP in effective in treating both alopecia areata and androgentetic alopecia.  If you have not done so already, blood work to test for lupus, thyroid dysfunction, anemia, low vitamin D, and nutritional deficiencies.  A more recent biopsy may be needed.  Avoid styles that add pressure to the scalp such as weaves and extensions.  A topical regimen with minoxidil and a topical steroid may be helpful.  You may also benefit from kenalog injections in addition to the PRP to the new sites of hair loss.

I advise re-evaluation by a board-certified dermatologist to rule out another cause for the worsening bald patches on the back of your scalp. It's possible that you are now experiencing alopecia areata,  a distinct type of hair loss that is auoimmune in nature and usually diagnosed by a good clinical exam. While PRP may be used to treat alopecia areata it would not be the first line treatment. Typically steroid injections or topical steroids to induct growth for localized patches. See an expert for an evaluation (including any pertinent blood tests) and discussion of treatment options. For the background AGA continuing with PRP may be beneficial as will oral treatment with medications such as spironolcatone and finasteride. Good luck!