90 lb weight loss and bald spot on back of my head

20 Y/O male here. Made a doctors appointment, he said my hair looks like its thinning but he thinks it’s from losing 90 lbs in 7 months or from other causes. I then asked to see a dermatologist but will a derm be able to tell if it’s TE or balding? I know everyone wants it to be Telogen Effluvium but I had a awful diet and other signs of TE (beau’s nails). I’m worried the dermatologist won’t be able to tell the difference and won’t be able to give me a definitive answer. 

Men rarely get Telogen Effluvium but balding is common. Get a HAIRCHECK test to find out if you are balding. https://baldingblog.com/2017/01/10/value-haircheck-bulk-measurements-two-patients-seen-today/