Cold sore

Can anyone help? I have a cold sore on the corner of my mouth that is almost healed completely over the past week but every time try to eat or even yawn it bleeds and scabs and then bleeds again. I usually take the prescription pills for them but I can’t get anymore, at least for a while. I don’t know what to do anymore, I have been putting abreva on it but this last stage is the worst. Any tips would be greatly appreciated.