Facebook stock took a hit this week post-earnings, but Private Advisor Group's Guy Adami said that now is the time to buy.

"We've been in a very well defined uptrend for a year," he told CNBC. "If I am wrong, you stop out below the Oct. 14 low of $72.05. If I'm right, you take profits at $85."

Despite beating analysts' expectations for the third quarter and warning about an increase in spending for the year, Facebook saw its stock sell off more than 10 percent.

Read More Facebook shares drop on guidance, increased costs

Shares of Facebook are up more than 50 percent in the past year.