Hello and welcome! Skin reactions as well as muscle/joint pain can potentially be a side effect of anti-thyroid drugs, so I would definitely mention this to your doctor ASAP.
Some patients do struggle with weight on ATDs (I'm one!), but others do not. The scale can fluctuate for *many* reasons (water weight, time of month, etc.), so it's quite possible that this reading was a fluke.
Take care - and please check back to let us know how you are doing!
GDATF Forum Facilitator
…through nature's inflexible grace, I'm learning to live…
– Dream Theater