I traveled to Solstheim via boat thinking that if I swam to the arrow it would rediscover the fast travel option, but this did not happen. In doing so I had to rediscover the main cities, which was odd, but the worst thing that had happened was the arrow to Solstheim and back to Skyrim was missing. I decided to console command speedmult so that I could rediscover everything quickly without reloading my last save which had been hours before. To use the console, simply type using the keyboard. This brings up a pop-up window in which you can enter text commands.

You can access the Console by hitting the or key on your keyboard (right under ESC). Since I did not want to have discovered everything automatically, which includes the Beyond Skyrim mods and such I reset the tmm to default basically, (can't remember the #'s) however when I did this all existing locations became undiscovered. Console Commands in The Elder Scrolls V: Skyrim (Special Edition) are used as a debugging tool for PC players. One day when I was wondering if I had indeed discovered all location I decided to use the console command 1,1,1 to show all locations, but without thinking I had forgotten to save.

Skyrim fast travel console