Disappearing squamous cell carcinoma metastatic

Hi all, im writing this because I am worried that I have CUP (cancer of unknown primary) except I know where the primary was? Sorry for the long story and this might sound stupid but is it possible for a squamous cell carcinoma to disappear then metastasize? I am sure that I had what I now believe to be bowens disease on my scrotum which I feel then turned into squamous cell carcinoma, had the characteristics itchy, bleeding now and again. I dismissed it because of the area it was in and could forget about it and attributed it to the fact that I was working out every day (I was a bodybuilder) and assumed it was like a jock itch. That lesion seemed to get smaller though after about 2 years and seemed to completely heal up apart from a slightly different coloured area of skin. But a couple months after it healed up my scrotum swelled up on the left hand side where it was, went to the doctor she prescribed me ofloxacillin as the thought it was a bacterial infection. I took the ofloxacillin and the swelling went away within a month, however, a month after that I had a fever and was ill for a week. A month after that, I noticed 1 swollen cluster of lymph nodes in my groin went to the doctor they said it was because of the fever, so didn't worry. Then 2 months after that I started having bleeding from my oral cavity, like when I would spit there would always be blood in it, left it for a bit, but then noticed lymph nodes in my neck were swollen, went to the doctors sent me for chest x ray and e.n.t. who examined my oral cavity fully and put the camera up my nose and down throat said there was nothing abnormal and sent me for a ct scan of chest and thorax, which came back clear. Waited 2 months lymph nodes were still there so doctor sent me for an ultrasound of groin and neck went for that and doctor performing ultrasound said they appeared completely benign and tried to reassure me that they were. Can an ultrasound determine benign and malignant? Im now 6-7 months still spitting blood and still swollen lymph nodes, with some fatigue. I saw a private ent who said the same. Now my doctor wont do any more tests because he feel that I just have health anxiety and I don't feel he is taking me seriously. I've basically had to beg him to give me a referral for a private whole body pet/ct scan which I haven't had yet. By the way which would I be better off having, pet/ct or mri? I'll be honest this whole debacle has taken over my life and is all I can think about. My doctor said he won't do a biopsy because he feels the ultrasound is enough to know and feels that he knows there's nothing. Not really good enough for me lol! So sorry for the life story but need some answers and had to explain fully, my main question is can a squamous cell carcinoma disappear/heal over then metastasize?

Thanks,

Jake.