Yes, your condition may worsen after starting the treatment for Hansen's disease. Some patients experience a reaction to the medication once treatment has begun. This is a response of the immune system to dead or dying bacteria and can cause worsening of the rash or a painful neuritis, which can affect sensation and/or strength.
Reactions can be mild or severe. If mild, no treatment or only over-the-counter anti-inflammatory medication may be sufficient. Severe reactions can be harmful to the nerves and need prompt treatment. If you think you are having a reaction of any type, notify your physician so that he can decide on the appropriate form of treatment.
This answer is based on source information from the U.S. Department of Health and Human Services