Thanks for the report. I’m planning to put out a hotfix here soon that should at least reset the issue for the moment. Do you remember anything further about what happened between you being able to use the pick and not use it? Also was it just the pick that stopped working or everything? Usually when I hear about a bug like this everything stops working not just one tool.
The only tool I had with me was the pick, so I don't know about the rest of them. If it happens again I will go home and check the rest of the tools also. I had ores, bars, stones and a flower in my inventory.
Also it was the first thing I did that day, go to the mines. I didn't even have to use the watering can before because it was raining.
I exit the game and when I loaded again everything worked well so... I don't know.