Pacman Frog- Possible infection?

Question
Information requested below. I received this pacman about 3 weeks ago from a local pet store. It is slightly smaller than the Palm of my hand. It has never eaten for me since I brought it home. I attempted every couple of days as to avoid stressing it out but it never seems interested despite the variety or circumstance. It deficated twice within the first few days, shed once. It spends most of its time under its hollow log. The substrate stays moist but not soaking. I have changed it once. I always treat all water entering tank with reptile water dechlorinizer. It's seemed healthy up until today when I decided to attempt force feeding. It has a slightly raised, round swelling on top left portion of its abdomen.when I wiped the substrate away I noticed a small opening. I used a moist cotten swab to probe the outside and a white discharge came out of the hole.I'm assuming this is an abscess. I'm wondering what may have caused this, what I should do differently, and what are the chances of survival? I am fully prepared to take it to the vet but may not be able to get an appointment until Wednesday. Any advice would be helpful. Thank you for your time and expertise.

species;Pacman
habitat size; 10 gallon aquarium
substrate; Coconut fiber
humidity%; 75-80%
bask/ambient temps;75-85
lighting: wattage, brand, and type of UVB(tube, coil, spot/flood);indirect daylight, red heat lamp at night if cold
vet history; N/A
all food offered; crickets, wax worms, nightcrawlers
feeding schedule;Attempt once every 3 days
supplements and schedule;D3 calcium powder every other week
last time ate; Tonight - force fed 1 nightcrawler
when and how water is given;moist substrate, misting, shallow water dish for soaking
when last defecated;2 weeks ago
captive bred or wild caught;captive bred shed recently; 1.5 weeks ago
other animals living in same terrarium?No

Answer
This pretty much sounds like a vet trip is in order if you have an open wound in the abdomen, discharge of any kind, and loss of appetite for 3 weeks. I will need to see a photo of this wound. From a good camera with good lighting and focus.

Additionally, I see a few issues to bring up. Discontinue the D3 supplementation. Despite what you've heard it's dangerous. Use only a calcium only powder for calcium. D3 is a regulating hormone which the average person should not be using, and is also a substance found in rat poisons for it's efficiency in causing soft tissue calcification.  

Also, you should ditch the red night light. These are bad too. This is horribly agitating to herptiles, as they see very well in this spectrum, so it can keep them awake excessively. You should instead use a small ceramic heat emitter on one end, suitably positioned so it doesn't create excessive desiccation, OR an undertank heater separated from the frog by a sufficient amount of substrate.

Lastly, indirect sunlight is likely not going to be sufficient here, especially if you are using a window. In the wild these are generally diurnal frog, so you are going to need at least low intensity UVB lighting, such as a 2-3% UVB linear tube (NOT A COMPACT AND NOT A COIL).