Can Invisalign cause gums to bleed and open the gum sockets?

My gums are sensitive and I noticed they bleed when I floss and they also look a bit swollen. To add, i use Invisalign retainers. I went to a dentist and he recommended the Arestin treatment. The gums do not look severe however it is a bother. Is there another alternative to the Arestin? I find this treatment too pricey for my condition. Should I look for another dentist for a second opinion? Any advice would be greatly appreciated! Thank you.