You're not the only one on here to have severe SS symptoms without raised markers. And I'm puzzled as to why your ophthalmologist is insisting you can't get a diagnosis of SS without corneal problems. I'm sure there will be plenty of us on here who don't agree with his opinion.
I'll try and re-construct the progress of my symptoms, though it all started more than 20 years ago now.
The dry mouth came first. I kept noticing a stale taste in my mouth and my lower lip sticking to my gums. But I've always been OK when actually eating, as long as I avoid things like dry bread or crackers. Then I developed deep, painful cracks at the corners of my mouth that kept splitting and bleeding when I opened my mouth to eat. This continued on and off for about a year. My GP told me it was allergy (which I knew it wasn't) and my dentist couldn't see anything wrong. I also got a raised, sore rash (probably fungal) on my upper lip during that time.
The mouth problems died down to manageable levels, only to be followed by peripheral neuropathy. Initially, altered sensation in one big toe, but spreading to all my extremities over the next ten years. This stopped abruptly (literally overnight!) ten years later, though it still occasionally comes back now. During the same period I started getting sore, sticky eyes, with frequent attacks of conjunctivitis. I got the same bleeding cracks at the corner of one eye as I'd had in my mouth. This eventually died down too, though still recurs from time to time, especially in the last few months.
In the next few years I suddenly started getting Reynaud's syndrome, for the first time in my life. One day my entire left hand went cold and white, even though it was a warm day. I also woke some days with my left hand fixed in a painful claw that I couldn't open till around midday. I saw various specialists - dentist, ophthalmologist, dermatologist, rheumatologist but they all said there was nothing wrong except mild inflammation. By this time I was starting to get very tired too, and was losing quite a lot of hair. My GP said it was all down to old age (I was about 55 at the time!) until the day I managed by pure chance to throw an impressive Reynaud's attack while actually in her office. That was when she ordered the blood test for anti-salivary gland antibiodies. She also sent me to an endocrinologist, who ordered a special urine test which diagnosed "covert hypothyroidism". My TSH had been sky-high for years, but as my T3 and T4 had always been at the low end of normal my GP had insisted I didn't have a thyroid problem.
I don't take any medications to relieve my symptoms, except for homeopathic remedies when I have an arthritis flare-up, and a mucolytic most nights. This is because I also have a tendency to very thick catarrh that clogs my air passages and causes sleep apnoea. I take bromhexine (Bisolvon), which I don't believe is available in the UK - if that's where you are. I use basic tear-replacement drops, though I sometimes used the more expensive ampoules when my eyes were very sore. These don't contain any preservatives, but neither kind is reimbursed by my medical insurance, so I use the ordinary kind as far as possible. During the period when I kept getting conjunctivitis, my GP prescribed chloramphenicol drops. Oh, and I take thyroxine for my under-active thyroid, but that's not strictly a medication. And that's it. Then again, my symptoms aren't very bad most of the time and can usually be managed by life-style measures. But there are plenty of people on this forum who will be able to advise you about meds.