I would hold off on any solid foods for a couple of days. They will increase the risk of impaction- which is very possible in this case. Their bodies are not made to digest this sort of material. Most paper towels are also bleached so even if his body could digest it, it wouldn't be good for him. He should be able to pass since he is a larger frog, but he is still at risk. You will have to monitor him very closely for the next few days. I would get him a dose of Reptiaid. Give him a soak like Namio said. Keep his temps up for the next few days. Heat aids with digestion. Try to keep his enclosure 81-82 degrees during the day and around 78 at night. Keep his humidity up as well.

It is important to remember that these are ambush preditors. Their natural instinct is to bite and swallow anything that moves near them even if it turns out to be a foreign object not food. Other people have lost frogs to similar occurances. Non-digestable materials can cause impaction and death. Keep a very close eye on him.

Keep us posted.