"painful bumps on my scalp... I have a suspicion I'm failing Humira as I feel like crap, my joints are very sore and I'm exhausted...."
I would contact your gasteroenteroligist and mention these potential side effects. Have you had a test to see if you've developed antibodies to Humira? I ask as side effects become a lot more likely when antibodies are present, and you're describing that sort of thing: skin rashes, joint pains, fatigue, etc. When our immune system is actively fighting the humira within us then it shows up in those sorts of ways.
Promethus Labs in CA originally developed the antibody test for Humira/adalimumab and still sells it for a premium. It's a simple blood test and results come in within a few days time.
/www.anserifx.com/ Other labs now offer a generic version of that test for a much more reasonable cost, including Labcorps and other labs as well. Call your local labs and ask if they offer a generic.
/www.labcorp.com/test-menu/18766/adalimumab-concentration-and-anti-adalimumab-antibody--serial-monitorIf you have confirmed antibodies, then you should switch to another biologic, which will stop the medication induced symptoms over time, and also control your Crohn's (as humira did before the issues popped up). If Humira worked for you then consider another tnf-alpha-based biologic: Remicade or Simponi. Having antibodies to Humira does not mean you'll get antibodies to another tnf-alpha biologic. They are all different enough in molecular structure that your immune system has to develop a different antibody to stop remicade/simponi. You can consider adding an immunomodulator to reduce the odds of future antibody formation to a different biologic: methotrexate/azathioprine/imuran/6mp.
Good luck!