VA reopened an approved claim from 3 years ago

Im service connected for sinusitis/rhinituis and recently had an HLR contesting their denial of sleep apnea secondary to these two conditions. I now see my claim, where I was awarded a percentage for sinusitis/rhinitus several years ago, has been reopened. Why would this be? Does this mean they may propose a reduction or order a new c&p for these two conditions? I'm sweating bullets.