Hi - hope things are improving - usually within 10-14 days post surgery they have you eating. I would ask if you can try non chew foods, smoothies, milk shakes, pudding, ice cream etc... and if and when you do start to chew, it should be on the good side. Eating is fun but you need to be super careful of cleanliness after that. I would invest in a water pik and use it on the lowest setting, to get rid of any left over foods that can hide. Almost everyone who has had your surgery has a huge tongue afterwards. It's due to swelling and a build up of lymph fluids from the neck dissection. (the regular drainage pathways have been interrupted)
This should not deter you... just be super careful.

As for the rads and chemo... if they are offering get clarification - however, my advice is go with it if they have a good reason. Too often it is not offered and there are recurrences that can be deadly. Hugs and healing vibes to you.