Is this scarring alopecia? No derm has said anything about it (Photo)

I'm sorry to hear that you're experiencing this distressing issue. Hair loss can be caused by a variety of factors, and in your case, it seems there might be multiple contributing factors.
Accutane is known to cause hair loss in some patients, which usually resolves once the medication is stopped. However, as your biopsy revealed possible Telogen Effluvium (TE), Androgenetic Alopecia (AGA), and folliculitis, it's clear that your situation may be more complex.
A trichoscopy could indeed be a useful next step. Trichoscopy is a non-invasive method that allows for the evaluation of hair and scalp disorders. It could provide more insight into the cause of your hair loss and guide further treatment decisions.
In the meantime, consider the following general advice:1. Avoid hairstyles or treatments that can cause tension or damage to your hair and scalp.2. Maintain a healthy diet rich in proteins, vitamins (especially vitamin D and E), and minerals (like iron and zinc) that support hair health.3. Manage stress through relaxation techniques as stress can exacerbate hair loss.
Finally, it's important that you continue to work closely with your dermatologist to manage this issue. They can guide you through the process, provide appropriate treatment options, and monitor your progress. It may also be beneficial to seek a second opinion from another dermatologist or a trichologist (a specialist in hair and scalp disorders) for additional insights.

From the photo, I doubt it is a type of scarring alopecia, but it is hard to be sure. Trichoscopy would be a good option. Sometimes in my clinic a trichoscopy yields more answers than scalp biopsies. Please keep in mind that the person who performed your scalp biopsy may have not have sampled the area that would produce a correct diagnosis. This is called sampling error and is very common with scalp biopsies. Other information would be helpful such as medical history, family history and of course a physical exam by a specialist dermatologist.

If the biopsy was taken from a representative area, then the chances of scarring alopecia are very low. You need to keep in mind that the way we diagnose hair loss is always the same. We listen to the patient’s story and then fully examine the scalp (including trichoscopy) and then do any other tests we need. Trichoscopy alone is not so helpful as one always needs to tie it back to the main story of the patient and see if it fits. Some clinicians are good at trichoscopy and others are less experienced so trichoscopy is only as good as the user of the trichoscopy device. All in all, you have provided one photo here and limited story. One can never say the diagnosis with certainty without a full review of the story and full review of every square inch of the scalp. In these photos, there hair thinning which may be TE or AGA ( or both). The photo is not a photo of alopecia areata and not a typical photo of scarring alopecia. More information, and more photos would take this a bit further but nothing replaces a full review of all the pieces of the puzzle.