Dear Phuong Thank you for your question. I agree with Dr Maddahi where I would suggest seeing your dentist to evaluate the area. A radiograph (x-ray) should be taken to evaluate the condition of the implant and check the health of the bone, which may not be visible to you. As it is a narrow area of recession, a gum tissue graft would help cover the area if there is no bone loss next to the implant. It may be useful to gently massage the gum tissue downwards to help stimulate the gum tissue. I would also advise being careful about brushing. Make sure that you brush gently in that area, using downward strokes to gently massage the gum tissue. I would also advise using a soft toothbrush if you are not already doing so. Based on the picture you have posted, it doesn't look like there's any inflammation or acute conditions happening. You should probably be just fine to go on your trip without worrying about problems. I hope you have a lovely trip! Kind Regards John