Skin rashes and hives are a common reaction to many anorectic medications. Dry itchy skin does improve over time. Regular use of lotion, especially after showering will help keep the dryness and itching under control. There is nothing in the literature about anaphylaxis or other serious allergy problems resulting from the use of obesity medications. If it doesn't get better or stay the same with treatment you should call your doctor before the next regular visit.
Insomnia is a common initial side effect of adrenergic drugs.
Generally it goes away in a few weeks. These are a few of the things your doctor may recommend. Take the medication as early in the morning as possible. Lower the dose for the first few weeks, or possibly even long term. The 8 mg pill is scored down the middle, so you can change your dose in 4 mg increments, if necessary.