The solution is to keep the metal object away from your skin. My doctor ordered folic acid at 0.5 mg daily to prevent heart problems. I got very sick on this dose. As a matter of fact, 0.1 mg makes me nauseous. Methotrexate is more likely to make you nauseated than folic acid.
Some doctors prescribe folic acid to help with the nausea caused by methotrexate.
If your psoriasis is quite itchy, then antihistamines such as Benadryl or Atarax may provide some relief. These medications also have a sedative effect. I recommend that you consult with a dermatologist to determine what is best in your particular case. I strongly advise close follow-up with your ophthalmologist, as iritis can lead to vision loss if not adequately treated. Last year my dermatologist determined that Dovonex was causing my phosphorus level to drop.