Have doctor break your waterbag? Induce will be very painful and the pain relief that you took only last for 6 hours is the jab on thigh, am I right? If pain is unbearable you can choose to take epidural or gas. Your dilation is taking pretty slow and if this continue to take more than expected, anything can happened to baby and you may end up in emergency c section. This is based on friend's experience.
I was induced for first child and spend about 16/17 hours in labour. I took jab, gas and ended with epidural and vaginal assisted delivery (vacuum). But, when I was induced, I am already 3cm dilated and dilation took very long even after doctor break the waterbag.
Do choose your option wisely and seek advice with doctor as they check you.