Some sort of brown stuff all over tongue with much more at the back. can scrape off but more comesback. large red lumps all over tongue. what is this?

Sinus drainage: Keep cleaning your tongue as the post nasal drip is full of organisms that will cause infections. See your physician for an antibiotic for sinus infection.

Unknown: If you have had pepto bismol (bismuth subsalicylate) last night you can wake up with brown stuff on your tongue. Also, smoking and lack of dental hygiene can cause a buildup of organic debris on your tongue. Invest in a tongue scraper ( less than a couple of bucks at your local pharmacy ). Clean your tongue twice a day when you brush your teeth. If it still persists, see your dentist.

Brown tongue: Is usually caused by plaque, staining, debris, bacteria especially in patients that smoke & drink lots of coffee. Red bumps are probably normal of more likely inflamed papillae (taste buds). Just like you have to brush\floss your teeth & shower or bath every day, you should use a tongue blade to keep your tongue clean. All this is conjecture, see your own dentist for exam & accurate appraisal.