Exploring different types of sexual play is fun but seeing blood stains in the process is not so much fun.
Most of the time, scratches or cuts are very small and heal on their own within a few days. Although the risk of infection is already low, you can further reduce it by having your partner cover their hands with a condom or disposable glove.
This will lower the possibility of them introducing bacteria into your vagina and the cuts. Even if you're not using gloves, it's a good idea to have your partner wash their hands before you start having sex.
But using a little bit of water-based lube will help to lower the chance of getting cuts because it allows your partner to slip their fingers in and out with less friction. That is why lubrication is very important.
The vagina produces lubrication during arousal, but this can take time and foreplay. So be sure to go slow, stop if it feels uncomfortable, and most importantly, communicate about what feels good and what doesn’t.
Small cuts are the most common reason someone might bleed after being fingered, there are a few other possibilities. Your partner's fingers might have stretched your hymen. The hymen is a thin tissue that stretches over the opening of some people’s vaginas, so stretching it can cause it to bleed.
There's also the chance that you're spotting between periods, which might not be related to the fingering at all, just bad timing. Vaginal infections or STIs can also cause spotting, but this will come with other symptoms such as vaginal discharge and pain while you pee.
But there's no reason to worry if you notice a little bit of blood, but you can check in with a doctor if you have any pain, discomfort or if the bleeding doesn't go away within a few days.