Can I get a body massage 3 hours after getting Botox in my front neck area?

Botox can migrate (spread) after injection, especially when pressure is applied. There is a risk that if this happens, you may not get your desired result. Ultimately, you should discuss your plans with your injectionist and receive clearance from them before proceeding with your massage.

A massage limited to your body and not involving your neck area should not be a problem 3 hours after having received a Botox treatment to the front of your neck.  

I generally tell my patients to wait 24 hours before having a facial massage after Botox.  I would check with your physician and confer which areas were treated and if they think it is safe to have the neck massaged.