Ripped front camera flex cable. Phone now overheating. Temp fix?

I just replaced the battery in an iPhone 6 Plus. I made the rookie mistake of ripping the flex cable going to the front camera and earpiece. I had NOT removed the display and instead just worked with the phone carefully propped up and rubber-banded to something weighted. That one flex cable is way more fragile than I expected.

The phone still otherwise functions fine, other than the front camera (obviously) and the earpiece. Others on calls don’t seem to notice any change in call quality. I ordered a replacement flex cable, but figured I could still use the phone while I was waiting for it - I’d just have to use the speakerphone or a headset on calls, and I wouldn’t be able to take selfies (good thing I’m not a selfie fanatic!).

After first reassembling the phone, it worked fine but it would overheat within a minute. Sometimes it would reboot suddenly (assuming from the overheating). The heat was in the top right corner (seen from the front) right near the back camera lens. I reopened the phone and noted that this area did not overheat when the phone was running while open, so my theory was that the flex cable was somehow just barely shorting out against the metal shield covering the board connectors. Figured for a temporary fix I’d put a piece of Kapton tape down over the metal shield; after this the phone did not overheat anymore when closed up, so I figured I was good to go for now. I charged the new battery to 100% and went on with my day. The phone did get a little warm during charging, but once it reached 100% it cooled down to normal temperature.

However, after being on a phone call for around 25 minutes, the phone slowly heated up to the point of thermal shutdown (“Your iPhone needs to cool down”). The heat is concentrated in the same spot as before. I didn’t notice it heating up because it was on the table on speakerphone, and only found out when my call ended suddenly with that message. The phone was definitely hot in the same space as before.

Is there something I can do temporarily to keep the phone in working order while I wait for that replacement cable? Is my theory likely correct on why I’m suddenly getting overheating (the ripped cable causing partial short circuits)?