Very strange color combination, unfortunately intense coloration is often driven by stress. And turning pale right after doesn’t sound good. Be careful with the hot water bottle, you are on the right track with trying to keep him warm, but I’m a little concerned about the method you have chosen. Chams are cold blooded so what feels really warm to us feels very hot to them since their body temp is way below 98.6 degrees. Treat him like you would want to be treated in his situation. Would you want to be force fed? No judgment, just an honest question.
If I were you and not ready to let go I’d take his basking light and move it to the bottom of his viv, or wherever your keeping him now, so he can stay warm without the risk of falling. I’d also be reading up on how to force feed/water properly before I attempted it, if done wrong it will kill him. I hope the graphic below helps. If he makes it till morning take him out into the sun and give him as much direct sunlight and treats as he will accept. Congratulations on getting him to 7 years, it’s quite an accomplishment.
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