I'm fasting and I have very dry lips. I put Vaseline on one lip but it felt weird. I think I might have touched it with my other lip. I'm unsure whether or not I actually swallowed it because I don't think I did but it feels a little like I did. Is my fast valid?
Yes, your fast is valid since you did not mean to swallow what was on your lips because the Prophet ﷺ said,
إن اللهَ تجاوز عن أمتي : الخطأُ، والنِّسْيانُ، وما استُكْرِهوا عليه . الراوي : عبدالله بن عباس | المحدث : الألباني | المصدر : تخريج مشكاة المصابيح الصفحة أو الرقم: 6248 | خلاصة حكم المحدث : صحيح بمجموع طرقه
On the authority of Ibn Abbas (may Allah be pleased with him), that the Messenger of Allah (peace and blessings of Allah be upon him) said: Verily Allah has pardoned for [or been lenient with] my ummah: their mistakes, their forgetfulness, and that which they have been forced to do under duress.
Deemed Saheeh by the Al-Albani, 6248
Allah subhanahu wa ta’alla says,
وَلَيْسَ عَلَيْكُمْ جُنَاحٌ فِيمَا أَخْطَأْتُم بِهِ وَلَٰكِن مَّا تَعَمَّدَتْ قُلُوبُكُمْ وَكَانَ اللَّهُ غَفُورًا رَّحِيمًا ﴿الأحزاب:٥
And there is no blame upon you for that in which you have erred but [only for] what your hearts intended. And ever is Allah Forgiving and Merciful. (Al-Ahzab: 5)
In Majmoo’ al-Fataawa (19/224), Shaykh Ibn Uthaymeen responded to a question about using lip balm while fasting to treat dry lips, saying that it is allowed to use moisturizer on the lips and the nose, or to wet them with water using a cloth or something similar as long as the person avoids swallowing. However, if the person swallows by mistake after taking the precaution not to, fasting is still valid.
Check this link for more information https://islamqa.info/en/92923