I have been off methadone, now, for almost 4 weeks (very gradual withdrawal). For 17 years, I took 65 mg./day. In addition, I've worn a pacemaker for the past 2 years. Since coming off, I've developed a VERY strange problem. It seems my eyes when exposed to certain substances, INCLUDING MY OWN SWEAT, will burn, begin itching violently and, then, minutes later a horrible headache sets in which can last for hours.