95 skeeter has a leak around the drain plug

can anyone give me any tips on this i dont see any way to access from the inside

On some older boats its exposed,otther than open it up caulk just like when you bolt anything to it like engine,or screw any thing to it below the water line.
Id check the bottom of the hull for ground out spots as well its getting long in the tooth,for those or any thing larger most auto parts stores sometimes walmart stock a wet cabable fiberglass repair two part resin.
Whatever reason its leaking pays to find them and fix them as doesnt take but one season to start rotting wood.The resin is like two part play dough,easy to use and has fixed several ground out spots on my older boats quite well.If using it for the plug area keep it thin,after drying can sand and even paint to match if desired,keep it to 1/4 in all around should never notice it.

It indicates a potentially larger problem..... Something in that area has weakened enough to allow a crack or leak. It's right at the junction of the transom as well. This could be a very serious structural problem with the boat.

In order to do proper repairs, you're going to have to be able to get into this area.