This too shall pass.
When children go through big developmental shifts (approximately every 6 months in the first 5 years) the brain literally shuts down for re-wiring. If her brain was a tower of blocks, instead of just adding a sixth block, she is smashing down the tower and re-ordering the first 5 so that they are more stable and efficient. Neuron connections literally shut down and re-route. So temporarily, she loses access to whatever minimal coping skills she had maybe even a month ago. Potty training may regress, speech may regress.
Usually the process is somewhat gradual. So one area or two will appear to regress and then come back as others shut down for a while. Sometimes it's really intense and it seems everything is malfunctioning.
When our daughter was 2 1/2 she went through a really tough time and it lasted a few months. I eventually took her to see a doctor because she was soooo different. And then - it all passed and she'd made huge leaps verbally and physically. She's 3 1/2 now and we're sort of used to it. After 6 months of almost no tantrums, she's had 5 this week. Here we go again.... :)
lots of hugs and love. Be consistent and firm in setting your limits, but always loving and supportive of her struggle. So stop her from scratching and pinching, but don't punish her. Help her to find other ways of showing her frustration if you can. She already knows she shouldn't be doing it, but she has no other coping tools right now. It must be very frightening at 14 months to feel so much anger you scratch your own mother. Ignoring tantrums just teaches the kid that their biggest emotions are wrong. Which makes them feel that THEY are wrong. They're still feeling what they're feeling, they're just suppressing it. I think they need to be taught ways to cope with their emotions. And they need reassurance that they are still loved. And, of course, they don't get what they were screaming for.
around 14 months my own daughter went through a biting phase that lasted 2 months. it was sooooo stressful. But it passed.
and I too have on occasion given Tylenol "just to check if it's pain" :)
Some awesome books:
The highly sensitive child - Elaine Aron
Raising your Spirited Child - Mary Sheedy Kurcinka
Playful Parenting - Lawrence Cohen